Merge pull request #575 from Scrumplex/qt6

100 files changed, 2290 insertions, 596 deletions

diff --git a/launcher/Application.cpp b/launcher/Application.cpp
index c6e04a85..07658c5d 100644
--- a/launcher/Application.cpp
+++ b/launcher/Application.cpp
@@ -84,6 +84,7 @@
 #include <QDebug>
 #include <QStyleFactory>
 #include <QWindow>
+#include <QIcon>
 
 #include "InstanceList.h"
 
@@ -99,7 +100,6 @@
 #include "tools/JVisualVM.h"
 #include "tools/MCEditTool.h"
 
-#include <xdgicon.h>
 #include "settings/INISettingsObject.h"
 #include "settings/Setting.h"
 
@@ -1182,7 +1182,7 @@ void Application::setApplicationTheme(const QString& name, bool initial)
 
 void Application::setIconTheme(const QString& name)
 {
-    XdgIcon::setThemeName(name);
+    QIcon::setThemeName(name);
 }
 
 QIcon Application::getThemedIcon(const QString& name)
@@ -1190,7 +1190,7 @@ QIcon Application::getThemedIcon(const QString& name)
     if(name == "logo") {
         return QIcon(":/org.polymc.PolyMC.svg");
     }
-    return XdgIcon::fromTheme(name);
+    return QIcon::fromTheme(name);
 }
 
 bool Application::openJsonEditor(const QString &filename)
diff --git a/launcher/ApplicationMessage.cpp b/launcher/ApplicationMessage.cpp
index e22bf13c..ca276b89 100644
--- a/launcher/ApplicationMessage.cpp
+++ b/launcher/ApplicationMessage.cpp
@@ -1,11 +1,47 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "ApplicationMessage.h"
 
 #include <QJsonDocument>
 #include <QJsonObject>
+#include "Json.h"
 
 void ApplicationMessage::parse(const QByteArray & input) {
-    auto doc = QJsonDocument::fromBinaryData(input);
-    auto root = doc.object();
+    auto doc = Json::requireDocument(input, "ApplicationMessage");
+    auto root = Json::requireObject(doc, "ApplicationMessage");
 
     command = root.value("command").toString();
     args.clear();
@@ -25,7 +61,5 @@ QByteArray ApplicationMessage::serialize() {
     }
     root.insert("args", outArgs);
 
-    QJsonDocument out;
-    out.setObject(root);
-    return out.toBinaryData();
+    return Json::toText(root);
 }
diff --git a/launcher/BaseInstance.cpp b/launcher/BaseInstance.cpp
index 0efbdddc..5a84a931 100644
--- a/launcher/BaseInstance.cpp
+++ b/launcher/BaseInstance.cpp
@@ -39,6 +39,7 @@
 #include <QFileInfo>
 #include <QDir>
 #include <QDebug>
+#include <QRegularExpression>
 
 #include "settings/INISettingsObject.h"
 #include "settings/Setting.h"
@@ -335,7 +336,7 @@ QString BaseInstance::name() const
 
 QString BaseInstance::windowTitle() const
 {
-    return BuildConfig.LAUNCHER_NAME + ": " + name().replace(QRegExp("[ \n\r\t]+"), " ");
+    return BuildConfig.LAUNCHER_NAME + ": " + name().replace(QRegularExpression("\\s+"), " ");
 }
 
 // FIXME: why is this here? move it to MinecraftInstance!!!
diff --git a/launcher/BaseVersionList.cpp b/launcher/BaseVersionList.cpp
index aa9cb6cf..b4a7d6dd 100644
--- a/launcher/BaseVersionList.cpp
+++ b/launcher/BaseVersionList.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "BaseVersionList.h"
@@ -51,7 +71,7 @@ QVariant BaseVersionList::data(const QModelIndex &index, int role) const
     switch (role)
     {
     case VersionPointerRole:
-        return qVariantFromValue(version);
+        return QVariant::fromValue(version);
 
     case VersionRole:
         return version->name();
diff --git a/launcher/CMakeLists.txt b/launcher/CMakeLists.txt
index ec8e84c9..9708f65c 100644
--- a/launcher/CMakeLists.txt
+++ b/launcher/CMakeLists.txt
@@ -88,10 +88,10 @@ set(CORE_SOURCES
     MMCTime.cpp
 )
 
-ecm_add_test(FileSystem_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(FileSystem_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME FileSystem)  # TODO: needs testdata
 
-ecm_add_test(GZip_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(GZip_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME GZip)
 
 set(PATHMATCHER_SOURCES
@@ -338,7 +338,7 @@ set(MINECRAFT_SOURCES
     mojang/PackageManifest.cpp
     minecraft/Agent.h)
 
-ecm_add_test(minecraft/GradleSpecifier_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(minecraft/GradleSpecifier_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME GradleSpecifier)
 
 if(BUILD_TESTING)
@@ -347,7 +347,7 @@ if(BUILD_TESTING)
     )
     target_link_libraries(PackageManifest
         Launcher_logic
-        Qt5::Test
+        Qt${QT_VERSION_MAJOR}::Test
     )
     target_include_directories(PackageManifest
         PRIVATE ../cmake/UnitTest/
@@ -360,18 +360,18 @@ if(BUILD_TESTING)
 endif()
 
 # TODO: needs minecraft/testdata
-ecm_add_test(minecraft/MojangVersionFormat_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(minecraft/MojangVersionFormat_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME MojangVersionFormat)
 
-ecm_add_test(minecraft/Library_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(minecraft/Library_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME Library)
 
 # FIXME: shares data with FileSystem test
 # TODO: needs testdata
-ecm_add_test(minecraft/mod/ModFolderModel_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(minecraft/mod/ModFolderModel_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME ModFolderModel)
 
-ecm_add_test(minecraft/ParseUtils_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(minecraft/ParseUtils_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME ParseUtils)
 
 # the screenshots feature
@@ -393,7 +393,7 @@ set(TASKS_SOURCES
     tasks/SequentialTask.cpp
 )
 
-ecm_add_test(tasks/Task_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(tasks/Task_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME Task)
 
 set(SETTINGS_SOURCES
@@ -412,7 +412,7 @@ set(SETTINGS_SOURCES
     settings/SettingsObject.h
 )
 
-ecm_add_test(settings/INIFile_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(settings/INIFile_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME INIFile)
 
 set(JAVA_SOURCES
@@ -430,7 +430,7 @@ set(JAVA_SOURCES
     java/JavaVersion.cpp
 )
 
-ecm_add_test(java/JavaVersion_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(java/JavaVersion_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME JavaVersion)
 
 set(TRANSLATIONS_SOURCES
@@ -524,7 +524,7 @@ set(PACKWIZ_SOURCES
 )
 
 # TODO: needs modplatform/packwiz/testdata
-ecm_add_test(modplatform/packwiz/Packwiz_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(modplatform/packwiz/Packwiz_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME Packwiz)
 
 set(TECHNIC_SOURCES
@@ -549,7 +549,7 @@ set(ATLAUNCHER_SOURCES
     modplatform/atlauncher/ATLShareCode.h
 )
 
-ecm_add_test(meta/Index_test.cpp LINK_LIBRARIES Launcher_logic Qt5::Test
+ecm_add_test(meta/Index_test.cpp LINK_LIBRARIES Launcher_logic Qt${QT_VERSION_MAJOR}::Test
     TEST_NAME Index)
 
 ################################ COMPILE ################################
@@ -880,7 +880,7 @@ SET(LAUNCHER_SOURCES
     ui/instanceview/VisualGroup.h
 )
 
-qt5_wrap_ui(LAUNCHER_UI
+qt_wrap_ui(LAUNCHER_UI
     ui/setupwizard/PasteWizardPage.ui
     ui/pages/global/AccountListPage.ui
     ui/pages/global/JavaPage.ui
@@ -933,7 +933,7 @@ qt5_wrap_ui(LAUNCHER_UI
     ui/dialogs/ScrollMessageBox.ui
 )
 
-qt5_add_resources(LAUNCHER_RESOURCES
+qt_add_resources(LAUNCHER_RESOURCES
     resources/backgrounds/backgrounds.qrc
     resources/multimc/multimc.qrc
     resources/pe_dark/pe_dark.qrc
@@ -963,6 +963,7 @@ target_link_libraries(Launcher_logic
     tomlc99
     BuildConfig
     Katabasis
+    Qt${QT_VERSION_MAJOR}::Widgets
 )
 
 if (UNIX AND NOT CYGWIN AND NOT APPLE)
@@ -972,14 +973,15 @@ if (UNIX AND NOT CYGWIN AND NOT APPLE)
 endif()
 
 target_link_libraries(Launcher_logic
-    Qt5::Core
-    Qt5::Xml
-    Qt5::Network
-    Qt5::Concurrent
-    Qt5::Gui
+    Qt${QT_VERSION_MAJOR}::Core
+    Qt${QT_VERSION_MAJOR}::Xml
+    Qt${QT_VERSION_MAJOR}::Network
+    Qt${QT_VERSION_MAJOR}::Concurrent
+    Qt${QT_VERSION_MAJOR}::Gui
+    Qt${QT_VERSION_MAJOR}::Widgets
+    ${Launcher_QT_LIBS}
 )
 target_link_libraries(Launcher_logic
-    Launcher_iconfix
     QuaZip::QuaZip
     hoedown
     LocalPeer
@@ -1049,6 +1051,14 @@ if(INSTALL_BUNDLE STREQUAL "full")
                 COMPONENT Runtime
             )
         endif()
+        # TLS plugins (Qt 6 only)
+        if(EXISTS "${QT_PLUGINS_DIR}/tls")
+            install(
+                DIRECTORY "${QT_PLUGINS_DIR}/tls"
+                DESTINATION ${PLUGIN_DEST_DIR}
+                COMPONENT Runtime
+            )
+        endif()
     else()
         # Image formats
         install(
@@ -1091,6 +1101,16 @@ if(INSTALL_BUNDLE STREQUAL "full")
                 REGEX "\\.dSYM" EXCLUDE
             )
         endif()
+        # TLS plugins (Qt 6 only)
+        if(EXISTS "${QT_PLUGINS_DIR}/tls")
+            install(
+                DIRECTORY "${QT_PLUGINS_DIR}/tls"
+                DESTINATION ${PLUGIN_DEST_DIR}
+                COMPONENT Runtime
+                REGEX "_debug\\." EXCLUDE
+                REGEX "\\.dSYM" EXCLUDE
+            )
+        endif()
     endif()
     configure_file(
         "${CMAKE_CURRENT_SOURCE_DIR}/install_prereqs.cmake.in"
diff --git a/launcher/Commandline.cpp b/launcher/Commandline.cpp
index 2c0fde64..8e7356bb 100644
--- a/launcher/Commandline.cpp
+++ b/launcher/Commandline.cpp
@@ -1,18 +1,38 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
- * Authors: Orochimarufan <orochimarufan.x3@gmail.com>
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *      Copyright 2013-2021 MultiMC Contributors
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *      Authors: Orochimarufan <orochimarufan.x3@gmail.com>
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "Commandline.h"
@@ -47,7 +67,7 @@ QStringList splitArgs(QString args)
             if (cchar == '\\')
                 escape = true;
             else if (cchar == inquotes)
-                inquotes = 0;
+                inquotes = QChar::Null;
             else
                 current += cchar;
             // otherwise
@@ -480,4 +500,4 @@ void Parser::getPrefix(QString &opt, QString &flag)
 ParsingError::ParsingError(const QString &what) : std::runtime_error(what.toStdString())
 {
 }
-}
\ No newline at end of file
+}
diff --git a/launcher/FileSystem.cpp b/launcher/FileSystem.cpp
index 3837d75f..ebb4460d 100644
--- a/launcher/FileSystem.cpp
+++ b/launcher/FileSystem.cpp
@@ -1,4 +1,37 @@
-// Licensed under the Apache-2.0 license. See README.md for details.
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
 
 #include "FileSystem.h"
 
@@ -346,7 +379,7 @@ bool checkProblemticPathJava(QDir folder)
 }
 
 // Win32 crap
-#if defined Q_OS_WIN
+#ifdef Q_OS_WIN
 
 bool called_coinit = false;
 
@@ -366,7 +399,7 @@ HRESULT CreateLink(LPCSTR linkPath, LPCSTR targetPath, LPCSTR args)
         }
     }
 
-    IShellLink *link;
+    IShellLinkA *link;
     hres = CoCreateInstance(CLSID_ShellLink, NULL, CLSCTX_INPROC_SERVER, IID_IShellLink,
                             (LPVOID *)&link);
 
diff --git a/launcher/FileSystem.h b/launcher/FileSystem.h
index 31c7af70..fd305b01 100644
--- a/launcher/FileSystem.h
+++ b/launcher/FileSystem.h
@@ -1,4 +1,37 @@
-// Licensed under the Apache-2.0 license. See README.md for details.
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
 
 #pragma once
 
@@ -49,8 +82,8 @@ class copy
 public:
     copy(const QString & src, const QString & dst)
     {
-        m_src = src;
-        m_dst = dst;
+        m_src.setPath(src);
+        m_dst.setPath(dst);
     }
     copy & followSymlinks(const bool follow)
     {
diff --git a/launcher/GZip.cpp b/launcher/GZip.cpp
index 0368c32d..067104cf 100644
--- a/launcher/GZip.cpp
+++ b/launcher/GZip.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "GZip.h"
 #include <zlib.h>
 #include <QByteArray>
@@ -67,7 +102,7 @@ bool GZip::zip(const QByteArray &uncompressedBytes, QByteArray &compressedBytes)
         return true;
     }
 
-    unsigned compLength = std::min(uncompressedBytes.size(), 16);
+    unsigned compLength = qMin(uncompressedBytes.size(), 16);
     compressedBytes.clear();
     compressedBytes.resize(compLength);
 
@@ -112,4 +147,4 @@ bool GZip::zip(const QByteArray &uncompressedBytes, QByteArray &compressedBytes)
         return false;
     }
     return true;
-}
\ No newline at end of file
+}
diff --git a/launcher/InstanceImportTask.cpp b/launcher/InstanceImportTask.cpp
index dad2c1ad..14e1cd47 100644
--- a/launcher/InstanceImportTask.cpp
+++ b/launcher/InstanceImportTask.cpp
@@ -325,7 +325,7 @@ void InstanceImportTask::processFlame()
     // Hack to correct some 'special sauce'...
     if(mcVersion.endsWith('.'))
     {
-        mcVersion.remove(QRegExp("[.]+$"));
+        mcVersion.remove(QRegularExpression("[.]+$"));
         logWarning(tr("Mysterious trailing dots removed from Minecraft version while importing pack."));
     }
     auto components = instance.getPackProfile();
diff --git a/launcher/InstanceList.cpp b/launcher/InstanceList.cpp
index 3e3c81f7..fb7103dd 100644
--- a/launcher/InstanceList.cpp
+++ b/launcher/InstanceList.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QDir>
@@ -136,7 +156,7 @@ QVariant InstanceList::data(const QModelIndex &index, int role) const
     {
     case InstancePointerRole:
     {
-        QVariant v = qVariantFromValue((void *)pdata);
+        QVariant v = QVariant::fromValue((void *)pdata);
         return v;
     }
     case InstanceIDRole:
@@ -252,7 +272,7 @@ void InstanceList::setInstanceGroup(const InstanceId& id, const GroupId& name)
 
 QStringList InstanceList::getGroups()
 {
-    return m_groupNameCache.toList();
+    return m_groupNameCache.values();
 }
 
 void InstanceList::deleteGroup(const QString& name)
@@ -353,7 +373,11 @@ QList< InstanceId > InstanceList::discoverInstances()
         out.append(id);
         qDebug() << "Found instance ID" << id;
     }
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    instanceSet = QSet<QString>(out.begin(), out.end());
+#else
     instanceSet = out.toSet();
+#endif
     m_instancesProbed = true;
     return out;
 }
diff --git a/launcher/JavaCommon.cpp b/launcher/JavaCommon.cpp
index ae6cd247..4ba319b8 100644
--- a/launcher/JavaCommon.cpp
+++ b/launcher/JavaCommon.cpp
@@ -1,11 +1,47 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "JavaCommon.h"
 #include "java/JavaUtils.h"
 #include "ui/dialogs/CustomMessageBox.h"
 #include <MMCStrings.h>
+#include <QRegularExpression>
 
 bool JavaCommon::checkJVMArgs(QString jvmargs, QWidget *parent)
 {
-    if (jvmargs.contains("-XX:PermSize=") || jvmargs.contains(QRegExp("-Xm[sx]"))
+    if (jvmargs.contains("-XX:PermSize=") || jvmargs.contains(QRegularExpression("-Xm[sx]"))
         || jvmargs.contains("-XX-MaxHeapSize") || jvmargs.contains("-XX:InitialHeapSize"))
     {
         auto warnStr = QObject::tr(
@@ -19,7 +55,7 @@ bool JavaCommon::checkJVMArgs(QString jvmargs, QWidget *parent)
         return false;
     }
     // block lunacy with passing required version to the JVM
-    if (jvmargs.contains(QRegExp("-version:.*"))) {
+    if (jvmargs.contains(QRegularExpression("-version:.*"))) {
         auto warnStr = QObject::tr(
             "You tried to pass required Java version argument to the JVM (using \"-version:xxx\"). This is not safe and will not be allowed.\n"
             "This message will be displayed until you remove this from the JVM arguments.");
diff --git a/launcher/Json.cpp b/launcher/Json.cpp
index 37ada1aa..06b3d3bd 100644
--- a/launcher/Json.cpp
+++ b/launcher/Json.cpp
@@ -1,4 +1,37 @@
-// Licensed under the Apache-2.0 license. See README.md for details.
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
 
 #include "Json.h"
 
@@ -22,14 +55,6 @@ void write(const QJsonArray &array, const QString &filename)
     write(QJsonDocument(array), filename);
 }
 
-QByteArray toBinary(const QJsonObject &obj)
-{
-    return QJsonDocument(obj).toBinaryData();
-}
-QByteArray toBinary(const QJsonArray &array)
-{
-    return QJsonDocument(array).toBinaryData();
-}
 QByteArray toText(const QJsonObject &obj)
 {
     return QJsonDocument(obj).toJson(QJsonDocument::Compact);
@@ -48,12 +73,8 @@ QJsonDocument requireDocument(const QByteArray &data, const QString &what)
 {
     if (isBinaryJson(data))
     {
-        QJsonDocument doc = QJsonDocument::fromBinaryData(data);
-        if (doc.isNull())
-        {
-            throw JsonException(what + ": Invalid JSON (binary JSON detected)");
-        }
-        return doc;
+        // FIXME: Is this needed?
+        throw JsonException(what + ": Invalid JSON. Binary JSON unsupported");
     }
     else
     {
diff --git a/launcher/Json.h b/launcher/Json.h
index f2e68f0c..b11a356c 100644
--- a/launcher/Json.h
+++ b/launcher/Json.h
@@ -1,4 +1,37 @@
-// Licensed under the Apache-2.0 license. See README.md for details.
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
 
 #pragma once
 
@@ -29,8 +62,6 @@ void write(const QJsonObject &object, const QString &filename);
 /// @throw FileSystemException
 void write(const QJsonArray &array, const QString &filename);
 
-QByteArray toBinary(const QJsonObject &obj);
-QByteArray toBinary(const QJsonArray &array);
 QByteArray toText(const QJsonObject &obj);
 QByteArray toText(const QJsonArray &array);
 
diff --git a/launcher/LoggedProcess.cpp b/launcher/LoggedProcess.cpp
index 2479f4ff..fbdeed8f 100644
--- a/launcher/LoggedProcess.cpp
+++ b/launcher/LoggedProcess.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "LoggedProcess.h"
 #include "MessageLevel.h"
 #include <QDebug>
@@ -8,7 +43,11 @@ LoggedProcess::LoggedProcess(QObject *parent) : QProcess(parent)
     connect(this, &QProcess::readyReadStandardOutput, this, &LoggedProcess::on_stdOut);
     connect(this, &QProcess::readyReadStandardError, this, &LoggedProcess::on_stdErr);
     connect(this, SIGNAL(finished(int,QProcess::ExitStatus)), SLOT(on_exit(int,QProcess::ExitStatus)));
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(this, SIGNAL(errorOccurred(QProcess::ProcessError)), this, SLOT(on_error(QProcess::ProcessError)));
+#else
     connect(this, SIGNAL(error(QProcess::ProcessError)), this, SLOT(on_error(QProcess::ProcessError)));
+#endif
     connect(this, &QProcess::stateChanged, this, &LoggedProcess::on_stateChange);
 }
 
@@ -157,19 +196,6 @@ void LoggedProcess::on_stateChange(QProcess::ProcessState state)
     }
 }
 
-#if defined Q_OS_WIN32
-#include <windows.h>
-#endif
-
-qint64 LoggedProcess::processId() const
-{
-#ifdef Q_OS_WIN
-    return pid() ? pid()->dwProcessId : 0;
-#else
-    return pid();
-#endif
-}
-
 void LoggedProcess::setDetachable(bool detachable)
 {
     m_is_detachable = detachable;
diff --git a/launcher/LoggedProcess.h b/launcher/LoggedProcess.h
index e52b8a7b..61e74bd9 100644
--- a/launcher/LoggedProcess.h
+++ b/launcher/LoggedProcess.h
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *          http://www.apache.org/licenses/LICENSE-2.0
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #pragma once
@@ -43,7 +63,6 @@ public:
 
     State state() const;
     int exitCode() const;
-    qint64 processId() const;
 
     void setDetachable(bool detachable);
 
diff --git a/launcher/MMCZip.cpp b/launcher/MMCZip.cpp
index d7ad4428..f20d6dff 100644
--- a/launcher/MMCZip.cpp
+++ b/launcher/MMCZip.cpp
@@ -421,7 +421,7 @@ bool MMCZip::collectFileListRecursively(const QString& rootDir, const QString& s
             continue;
         }
 
-        files->append(e.filePath());  // we want the original paths for MMCZip::compressDirFiles
+        files->append(e);  // we want the original paths for MMCZip::compressDirFiles
     }
     return true;
 }
diff --git a/launcher/Version.h b/launcher/Version.h
index 9fe12d6d..aceb7a07 100644
--- a/launcher/Version.h
+++ b/launcher/Version.h
@@ -1,6 +1,42 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 
 #include <QString>
+#include <QStringView>
 #include <QList>
 
 class QUrl;
@@ -39,13 +75,21 @@ private:
                     break;
                 }
             }
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+            auto numPart = QStringView{m_fullString}.left(cutoff);
+#else
             auto numPart = m_fullString.leftRef(cutoff);
+#endif
             if(numPart.size())
             {
                 numValid = true;
                 m_numPart = numPart.toInt();
             }
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+            auto stringPart = QStringView{m_fullString}.mid(cutoff);
+#else
             auto stringPart = m_fullString.midRef(cutoff);
+#endif
             if(stringPart.size())
             {
                 m_stringPart = stringPart.toString();
diff --git a/launcher/VersionProxyModel.cpp b/launcher/VersionProxyModel.cpp
index b9a87c9c..032f21f9 100644
--- a/launcher/VersionProxyModel.cpp
+++ b/launcher/VersionProxyModel.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "VersionProxyModel.h"
 #include "Application.h"
 #include <QSortFilterProxyModel>
@@ -208,7 +243,8 @@ QVariant VersionProxyModel::data(const QModelIndex &index, int role) const
                         {
                             return APPLICATION->getThemedIcon("bug");
                         }
-                        auto pixmap = QPixmapCache::find("placeholder");
+                        QPixmap pixmap;
+                        QPixmapCache::find("placeholder", &pixmap);
                         if(!pixmap)
                         {
                             QPixmap px(16,16);
@@ -216,7 +252,7 @@ QVariant VersionProxyModel::data(const QModelIndex &index, int role) const
                             QPixmapCache::insert("placeholder", px);
                             return px;
                         }
-                        return *pixmap;
+                        return pixmap;
                     }
                 }
                 default:
diff --git a/launcher/icons/IconList.cpp b/launcher/icons/IconList.cpp
index d426aa80..3a223d1b 100644
--- a/launcher/icons/IconList.cpp
+++ b/launcher/icons/IconList.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "IconList.h"
@@ -86,7 +106,11 @@ void IconList::directoryChanged(const QString &path)
         QString &foo = (*it);
         foo = m_dir.filePath(foo);
     }
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    QSet<QString> new_set(new_list.begin(), new_list.end());
+#else
     auto new_set = new_list.toSet();
+#endif
     QList<QString> current_list;
     for (auto &it : icons)
     {
@@ -94,7 +118,11 @@ void IconList::directoryChanged(const QString &path)
             continue;
         current_list.push_back(it.m_images[IconType::FileBased].filename);
     }
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    QSet<QString> current_set(current_list.begin(), current_list.end());
+#else
     QSet<QString> current_set = current_list.toSet();
+#endif
 
     QSet<QString> to_remove = current_set;
     to_remove -= new_set;
diff --git a/launcher/icons/MMCIcon.cpp b/launcher/icons/MMCIcon.cpp
index f0b82ec9..436ef75f 100644
--- a/launcher/icons/MMCIcon.cpp
+++ b/launcher/icons/MMCIcon.cpp
@@ -1,21 +1,41 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "MMCIcon.h"
 #include <QFileInfo>
-#include <xdgicon.h>
+#include <QIcon>
 
 IconType operator--(IconType &t, int)
 {
@@ -63,7 +83,7 @@ QIcon MMCIcon::icon() const
     if(!icon.isNull())
         return icon;
     // FIXME: inject this.
-    return XdgIcon::fromTheme(m_images[m_current_type].key);
+    return QIcon::fromTheme(m_images[m_current_type].key);
 }
 
 void MMCIcon::remove(IconType rm_type)
diff --git a/launcher/java/JavaChecker.cpp b/launcher/java/JavaChecker.cpp
index 15b22260..041583d1 100644
--- a/launcher/java/JavaChecker.cpp
+++ b/launcher/java/JavaChecker.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "JavaChecker.h"
 
 #include <QFile>
@@ -53,7 +88,11 @@ void JavaChecker::performCheck()
     qDebug() << "Running java checker: " + m_path + args.join(" ");;
 
     connect(process.get(), SIGNAL(finished(int, QProcess::ExitStatus)), this, SLOT(finished(int, QProcess::ExitStatus)));
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(process.get(), SIGNAL(errorOccurred(QProcess::ProcessError)), this, SLOT(error(QProcess::ProcessError)));
+#else
     connect(process.get(), SIGNAL(error(QProcess::ProcessError)), this, SLOT(error(QProcess::ProcessError)));
+#endif
     connect(process.get(), SIGNAL(readyReadStandardOutput()), this, SLOT(stdoutReady()));
     connect(process.get(), SIGNAL(readyReadStandardError()), this, SLOT(stderrReady()));
     connect(&killTimer, SIGNAL(timeout()), SLOT(timeout()));
@@ -105,7 +144,12 @@ void JavaChecker::finished(int exitcode, QProcess::ExitStatus status)
     bool success = true;
 
     QMap<QString, QString> results;
+
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    QStringList lines = m_stdout.split("\n", Qt::SkipEmptyParts);
+#else
     QStringList lines = m_stdout.split("\n", QString::SkipEmptyParts);
+#endif
     for(QString line : lines)
     {
         line = line.trimmed();
@@ -114,7 +158,11 @@ void JavaChecker::finished(int exitcode, QProcess::ExitStatus status)
             continue;
         }
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+        auto parts = line.split('=', Qt::SkipEmptyParts);
+#else
         auto parts = line.split('=', QString::SkipEmptyParts);
+#endif
         if(parts.size() != 2 || parts[0].isEmpty() || parts[1].isEmpty())
         {
             continue;
diff --git a/launcher/java/JavaInstallList.cpp b/launcher/java/JavaInstallList.cpp
index 9b745095..0249bd22 100644
--- a/launcher/java/JavaInstallList.cpp
+++ b/launcher/java/JavaInstallList.cpp
@@ -1,21 +1,40 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QtNetwork>
 #include <QtXml>
-#include <QRegExp>
 
 #include <QDebug>
 
@@ -81,7 +100,7 @@ QVariant JavaInstallList::data(const QModelIndex &index, int role) const
     switch (role)
     {
         case VersionPointerRole:
-            return qVariantFromValue(m_vlist[index.row()]);
+            return QVariant::fromValue(m_vlist[index.row()]);
         case VersionIdRole:
             return version->descriptor();
         case VersionRole:
diff --git a/launcher/java/JavaUtils.cpp b/launcher/java/JavaUtils.cpp
index 24a1556e..c2b776ae 100644
--- a/launcher/java/JavaUtils.cpp
+++ b/launcher/java/JavaUtils.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QStringList>
@@ -177,25 +197,25 @@ QList<JavaInstallPtr> JavaUtils::FindJavaFromRegistryKey(DWORD keyType, QString
         archType = "32";
 
     HKEY jreKey;
-    if (RegOpenKeyExA(HKEY_LOCAL_MACHINE, keyName.toStdString().c_str(), 0,
+    if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, keyName.toStdWString().c_str(), 0,
                       KEY_READ | keyType | KEY_ENUMERATE_SUB_KEYS, &jreKey) == ERROR_SUCCESS)
     {
         // Read the current type version from the registry.
         // This will be used to find any key that contains the JavaHome value.
         char *value = new char[0];
         DWORD valueSz = 0;
-        if (RegQueryValueExA(jreKey, "CurrentVersion", NULL, NULL, (BYTE *)value, &valueSz) ==
+        if (RegQueryValueExW(jreKey, L"CurrentVersion", NULL, NULL, (BYTE *)value, &valueSz) ==
             ERROR_MORE_DATA)
         {
             value = new char[valueSz];
-            RegQueryValueExA(jreKey, "CurrentVersion", NULL, NULL, (BYTE *)value, &valueSz);
+            RegQueryValueExW(jreKey, L"CurrentVersion", NULL, NULL, (BYTE *)value, &valueSz);
         }
 
         TCHAR subKeyName[255];
         DWORD subKeyNameSize, numSubKeys, retCode;
 
         // Get the number of subkeys
-        RegQueryInfoKey(jreKey, NULL, NULL, NULL, &numSubKeys, NULL, NULL, NULL, NULL, NULL,
+        RegQueryInfoKeyW(jreKey, NULL, NULL, NULL, &numSubKeys, NULL, NULL, NULL, NULL, NULL,
                         NULL, NULL);
 
         // Iterate until RegEnumKeyEx fails
@@ -204,31 +224,32 @@ QList<JavaInstallPtr> JavaUtils::FindJavaFromRegistryKey(DWORD keyType, QString
             for (DWORD i = 0; i < numSubKeys; i++)
             {
                 subKeyNameSize = 255;
-                retCode = RegEnumKeyEx(jreKey, i, subKeyName, &subKeyNameSize, NULL, NULL, NULL,
-                                       NULL);
+                retCode = RegEnumKeyExW(jreKey, i, subKeyName, &subKeyNameSize, NULL, NULL, NULL,
+                                        NULL);
+                QString newSubkeyName = QString::fromWCharArray(subKeyName);
                 if (retCode == ERROR_SUCCESS)
                 {
                     // Now open the registry key for the version that we just got.
-                    QString newKeyName = keyName + "\\" + subKeyName + subkeySuffix;
+                    QString newKeyName = keyName + "\\" + newSubkeyName + subkeySuffix;
 
                     HKEY newKey;
-                    if (RegOpenKeyEx(HKEY_LOCAL_MACHINE, newKeyName.toStdString().c_str(), 0,
-                                     KEY_READ | KEY_WOW64_64KEY, &newKey) == ERROR_SUCCESS)
+                    if (RegOpenKeyExW(HKEY_LOCAL_MACHINE, newKeyName.toStdWString().c_str(), 0,
+                                      KEY_READ | KEY_WOW64_64KEY, &newKey) == ERROR_SUCCESS)
                     {
                         // Read the JavaHome value to find where Java is installed.
                         value = new char[0];
                         valueSz = 0;
-                        if (RegQueryValueEx(newKey, keyJavaDir.toStdString().c_str(), NULL, NULL, (BYTE *)value,
-                                            &valueSz) == ERROR_MORE_DATA)
+                        if (RegQueryValueExW(newKey, keyJavaDir.toStdWString().c_str(), NULL, NULL, (BYTE *)value,
+                                             &valueSz) == ERROR_MORE_DATA)
                         {
                             value = new char[valueSz];
-                            RegQueryValueEx(newKey, keyJavaDir.toStdString().c_str(), NULL, NULL, (BYTE *)value,
-                                            &valueSz);
+                            RegQueryValueExW(newKey, keyJavaDir.toStdWString().c_str(), NULL, NULL, (BYTE *)value,
+                                             &valueSz);
 
                             // Now, we construct the version object and add it to the list.
                             JavaInstallPtr javaVersion(new JavaInstall());
 
-                            javaVersion->id = subKeyName;
+                            javaVersion->id = newSubkeyName;
                             javaVersion->arch = archType;
                             javaVersion->path =
                                 QDir(FS::PathCombine(value, "bin")).absoluteFilePath("javaw.exe");
diff --git a/launcher/launch/LaunchTask.cpp b/launcher/launch/LaunchTask.cpp
index d5442a2b..3aa95052 100644
--- a/launcher/launch/LaunchTask.cpp
+++ b/launcher/launch/LaunchTask.cpp
@@ -282,6 +282,23 @@ void LaunchTask::emitFailed(QString reason)
     Task::emitFailed(reason);
 }
 
+void LaunchTask::substituteVariables(const QStringList &args) const
+{
+    auto variables = m_instance->getVariables();
+    auto envVariables = QProcessEnvironment::systemEnvironment();
+
+    for (auto arg : args) {
+        for (auto key : variables)
+        {
+            arg.replace("$" + key, variables.value(key));
+        }
+        for (auto env : envVariables.keys())
+        {
+            arg.replace("$" + env, envVariables.value(env));
+        }
+    }
+}
+
 QString LaunchTask::substituteVariables(const QString &cmd) const
 {
     QString out = cmd;
diff --git a/launcher/launch/LaunchTask.h b/launcher/launch/LaunchTask.h
index a1e891ac..2efe1fa2 100644
--- a/launcher/launch/LaunchTask.h
+++ b/launcher/launch/LaunchTask.h
@@ -1,18 +1,38 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Authors: Orochimarufan <orochimarufan.x3@gmail.com>
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Authors: Orochimarufan <orochimarufan.x3@gmail.com>
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #pragma once
@@ -85,6 +105,7 @@ public: /* methods */
     shared_qobject_ptr<LogModel> getLogModel();
 
 public:
+    void substituteVariables(const QStringList &args) const;
     QString substituteVariables(const QString &cmd) const;
     QString censorPrivateInfo(QString in);
 
diff --git a/launcher/launch/steps/PostLaunchCommand.cpp b/launcher/launch/steps/PostLaunchCommand.cpp
index 143eb441..cf765bc0 100644
--- a/launcher/launch/steps/PostLaunchCommand.cpp
+++ b/launcher/launch/steps/PostLaunchCommand.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "PostLaunchCommand.h"
@@ -27,9 +47,19 @@ PostLaunchCommand::PostLaunchCommand(LaunchTask *parent) : LaunchStep(parent)
 
 void PostLaunchCommand::executeTask()
 {
+    //FIXME: where to put this?
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
+    auto args = QProcess::splitCommand(m_command);
+    m_parent->substituteVariables(args);
+
+    emit logLine(tr("Running Post-Launch command: %1").arg(args.join(' ')), MessageLevel::Launcher);
+    const QString program = args.takeFirst();
+    m_process.start(program, args);
+#else
     QString postlaunch_cmd = m_parent->substituteVariables(m_command);
     emit logLine(tr("Running Post-Launch command: %1").arg(postlaunch_cmd), MessageLevel::Launcher);
     m_process.start(postlaunch_cmd);
+#endif
 }
 
 void PostLaunchCommand::on_state(LoggedProcess::State state)
diff --git a/launcher/launch/steps/PreLaunchCommand.cpp b/launcher/launch/steps/PreLaunchCommand.cpp
index 1a0889c8..bf7d27eb 100644
--- a/launcher/launch/steps/PreLaunchCommand.cpp
+++ b/launcher/launch/steps/PreLaunchCommand.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "PreLaunchCommand.h"
@@ -28,9 +48,18 @@ PreLaunchCommand::PreLaunchCommand(LaunchTask *parent) : LaunchStep(parent)
 void PreLaunchCommand::executeTask()
 {
     //FIXME: where to put this?
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
+    auto args = QProcess::splitCommand(m_command);
+    m_parent->substituteVariables(args);
+
+    emit logLine(tr("Running Pre-Launch command: %1").arg(args.join(' ')), MessageLevel::Launcher);
+    const QString program = args.takeFirst();
+    m_process.start(program, args);
+#else
     QString prelaunch_cmd = m_parent->substituteVariables(m_command);
     emit logLine(tr("Running Pre-Launch command: %1").arg(prelaunch_cmd), MessageLevel::Launcher);
     m_process.start(prelaunch_cmd);
+#endif
 }
 
 void PreLaunchCommand::on_state(LoggedProcess::State state)
diff --git a/launcher/main.cpp b/launcher/main.cpp
index 3d25b4ff..85fe1260 100644
--- a/launcher/main.cpp
+++ b/launcher/main.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "Application.h"
 
 // #define BREAK_INFINITE_LOOP
@@ -24,8 +59,10 @@ int main(int argc, char *argv[])
     return 42;
 #endif
 
+#if QT_VERSION <= QT_VERSION_CHECK(6, 0, 0)
     QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QGuiApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+#endif
 
     // initialize Qt
     Application app(argc, argv);
diff --git a/launcher/minecraft/GradleSpecifier.h b/launcher/minecraft/GradleSpecifier.h
index d9bb0207..27514ab9 100644
--- a/launcher/minecraft/GradleSpecifier.h
+++ b/launcher/minecraft/GradleSpecifier.h
@@ -1,7 +1,43 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 
 #include <QString>
 #include <QStringList>
+#include <QRegularExpression>
 #include "DefaultVariable.h"
 
 struct GradleSpecifier
@@ -25,20 +61,21 @@ struct GradleSpecifier
          4 "jdk15"
          5 "jar"
         */
-        QRegExp matcher("([^:@]+):([^:@]+):([^:@]+)" "(?::([^:@]+))?" "(?:@([^:@]+))?");
-        m_valid = matcher.exactMatch(value);
+        QRegularExpression matcher(QRegularExpression::anchoredPattern("([^:@]+):([^:@]+):([^:@]+)" "(?::([^:@]+))?" "(?:@([^:@]+))?"));
+        QRegularExpressionMatch match = matcher.match(value);
+        m_valid = match.hasMatch();
         if(!m_valid) {
             m_invalidValue = value;
             return *this;
         }
-        auto elements = matcher.capturedTexts();
-        m_groupId = elements[1];
-        m_artifactId = elements[2];
-        m_version = elements[3];
-        m_classifier = elements[4];
-        if(!elements[5].isEmpty())
+        auto elements = match.captured();
+        m_groupId = match.captured(1);
+        m_artifactId = match.captured(2);
+        m_version = match.captured(3);
+        m_classifier = match.captured(4);
+        if(match.lastCapturedIndex() >= 5)
         {
-            m_extension = elements[5];
+            m_extension = match.captured(5);
         }
         return *this;
     }
diff --git a/launcher/minecraft/MinecraftInstance.cpp b/launcher/minecraft/MinecraftInstance.cpp
index 889c6dde..abc022b6 100644
--- a/launcher/minecraft/MinecraftInstance.cpp
+++ b/launcher/minecraft/MinecraftInstance.cpp
@@ -473,25 +473,25 @@ QProcessEnvironment MinecraftInstance::createLaunchEnvironment()
 
 static QString replaceTokensIn(QString text, QMap<QString, QString> with)
 {
+    // TODO: does this still work??
     QString result;
-    QRegExp token_regexp("\\$\\{(.+)\\}");
-    token_regexp.setMinimal(true);
+    QRegularExpression token_regexp("\\$\\{(.+)\\}", QRegularExpression::InvertedGreedinessOption);
     QStringList list;
-    int tail = 0;
-    int head = 0;
-    while ((head = token_regexp.indexIn(text, head)) != -1)
+    QRegularExpressionMatchIterator i = token_regexp.globalMatch(text);
+    int lastCapturedEnd = 0;
+    while (i.hasNext())
     {
-        result.append(text.mid(tail, head - tail));
-        QString key = token_regexp.cap(1);
+        QRegularExpressionMatch match = i.next();
+        result.append(text.mid(lastCapturedEnd, match.capturedStart()));
+        QString key = match.captured(1);
         auto iter = with.find(key);
         if (iter != with.end())
         {
             result.append(*iter);
         }
-        head += token_regexp.matchedLength();
-        tail = head;
+        lastCapturedEnd = match.capturedEnd();
     }
-    result.append(text.mid(tail));
+    result.append(text.mid(lastCapturedEnd));
     return result;
 }
 
@@ -540,7 +540,11 @@ QStringList MinecraftInstance::processMinecraftArgs(
     token_mapping["assets_root"] = absAssetsDir;
     token_mapping["assets_index_name"] = assets->id;
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    QStringList parts = args_pattern.split(' ', Qt::SkipEmptyParts);
+#else
     QStringList parts = args_pattern.split(' ', QString::SkipEmptyParts);
+#endif
     for (int i = 0; i < parts.length(); i++)
     {
         parts[i] = replaceTokensIn(parts[i], token_mapping);
diff --git a/launcher/minecraft/OneSixVersionFormat.cpp b/launcher/minecraft/OneSixVersionFormat.cpp
index 879f18c1..cec4a55b 100644
--- a/launcher/minecraft/OneSixVersionFormat.cpp
+++ b/launcher/minecraft/OneSixVersionFormat.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "OneSixVersionFormat.h"
 #include <Json.h>
 #include "minecraft/Agent.h"
@@ -296,7 +331,7 @@ QJsonDocument OneSixVersionFormat::versionFileToJson(const VersionFilePtr &patch
     }
     writeString(root, "appletClass", patch->appletClass);
     writeStringList(root, "+tweakers", patch->addTweakers);
-    writeStringList(root, "+traits", patch->traits.toList());
+    writeStringList(root, "+traits", patch->traits.values());
     if (!patch->libraries.isEmpty())
     {
         QJsonArray array;
diff --git a/launcher/minecraft/PackProfile.cpp b/launcher/minecraft/PackProfile.cpp
index 01d42b00..5e76b892 100644
--- a/launcher/minecraft/PackProfile.cpp
+++ b/launcher/minecraft/PackProfile.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QFile>
@@ -688,7 +708,11 @@ void PackProfile::move(const int index, const MoveDirection direction)
         return;
     }
     beginMoveRows(QModelIndex(), index, index, QModelIndex(), togap);
+#if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
+    d->components.swapItemsAt(index, theirIndex);
+#else
     d->components.swap(index, theirIndex);
+#endif
     endMoveRows();
     invalidateLaunchProfile();
     scheduleSave();
diff --git a/launcher/minecraft/ProfileUtils.cpp b/launcher/minecraft/ProfileUtils.cpp
index 8ca24cc8..03f8c198 100644
--- a/launcher/minecraft/ProfileUtils.cpp
+++ b/launcher/minecraft/ProfileUtils.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "ProfileUtils.h"
 #include "minecraft/VersionFilterData.h"
 #include "minecraft/OneSixVersionFormat.h"
@@ -141,24 +176,6 @@ bool saveJsonFile(const QJsonDocument doc, const QString & filename)
     return true;
 }
 
-VersionFilePtr parseBinaryJsonFile(const QFileInfo &fileInfo)
-{
-    QFile file(fileInfo.absoluteFilePath());
-    if (!file.open(QFile::ReadOnly))
-    {
-        auto errorStr = QObject::tr("Unable to open the version file %1: %2.").arg(fileInfo.fileName(), file.errorString());
-        return createErrorVersionFile(fileInfo.completeBaseName(), fileInfo.absoluteFilePath(), errorStr);
-    }
-    QJsonDocument doc = QJsonDocument::fromBinaryData(file.readAll());
-    file.close();
-    if (doc.isNull())
-    {
-        file.remove();
-        throw JSONValidationError(QObject::tr("Unable to process the version file %1.").arg(fileInfo.fileName()));
-    }
-    return guardedParseJson(doc, fileInfo.completeBaseName(), fileInfo.absoluteFilePath(), false);
-}
-
 void removeLwjglFromPatch(VersionFilePtr patch)
 {
     auto filter = [](QList<LibraryPtr>& libs)
diff --git a/launcher/minecraft/ProfileUtils.h b/launcher/minecraft/ProfileUtils.h
index 351c36cb..5b938784 100644
--- a/launcher/minecraft/ProfileUtils.h
+++ b/launcher/minecraft/ProfileUtils.h
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 #include "Library.h"
 #include "VersionFile.h"
@@ -19,9 +54,6 @@ VersionFilePtr parseJsonFile(const QFileInfo &fileInfo, const bool requireOrder)
 /// Save a JSON file (in any format)
 bool saveJsonFile(const QJsonDocument doc, const QString & filename);
 
-/// Parse a version file in binary JSON format
-VersionFilePtr parseBinaryJsonFile(const QFileInfo &fileInfo);
-
 /// Remove LWJGL from a patch file. This is applied to all Mojang-like profile files.
 void removeLwjglFromPatch(VersionFilePtr patch);
 
diff --git a/launcher/minecraft/VersionFile.cpp b/launcher/minecraft/VersionFile.cpp
index f242fbe7..a9a0f7f4 100644
--- a/launcher/minecraft/VersionFile.cpp
+++ b/launcher/minecraft/VersionFile.cpp
@@ -89,14 +89,3 @@ void VersionFile::applyTo(LaunchProfile *profile)
     }
     profile->applyProblemSeverity(getProblemSeverity());
 }
-
-/*
-    auto theirVersion = profile->getMinecraftVersion();
-    if (!theirVersion.isNull() && !dependsOnMinecraftVersion.isNull())
-    {
-        if (QRegExp(dependsOnMinecraftVersion, Qt::CaseInsensitive, QRegExp::Wildcard).indexIn(theirVersion) == -1)
-        {
-            throw MinecraftVersionMismatch(uid, dependsOnMinecraftVersion, theirVersion);
-        }
-    }
-*/
diff --git a/launcher/minecraft/World.cpp b/launcher/minecraft/World.cpp
index dc756e06..dfcb43d8 100644
--- a/launcher/minecraft/World.cpp
+++ b/launcher/minecraft/World.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2015-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QDir>
@@ -321,7 +341,8 @@ bool World::install(const QString &to, const QString &name)
 
     if(ok && !name.isEmpty() && m_actualName != name)
     {
-        World newWorld(finalPath);
+        QFileInfo finalPathInfo(finalPath);
+        World newWorld(finalPathInfo);
         if(newWorld.isValid())
         {
             newWorld.rename(name);
diff --git a/launcher/minecraft/WorldList.cpp b/launcher/minecraft/WorldList.cpp
index 955609bf..aee7be35 100644
--- a/launcher/minecraft/WorldList.cpp
+++ b/launcher/minecraft/WorldList.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2015-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "WorldList.h"
@@ -195,7 +215,7 @@ QVariant WorldList::data(const QModelIndex &index, int role) const
         switch (column)
         {
             case SizeColumn:
-                return qVariantFromValue<qlonglong>(world.bytes());
+                return QVariant::fromValue<qlonglong>(world.bytes());
 
             default:
                 return data(index, Qt::DisplayRole);
@@ -215,7 +235,7 @@ QVariant WorldList::data(const QModelIndex &index, int role) const
     }
     case SeedRole:
     {
-        return qVariantFromValue<qlonglong>(world.seed());
+        return QVariant::fromValue<qlonglong>(world.seed());
     }
     case NameRole:
     {
@@ -227,7 +247,7 @@ QVariant WorldList::data(const QModelIndex &index, int role) const
     }
     case SizeRole:
     {
-        return qVariantFromValue<qlonglong>(world.bytes());
+        return QVariant::fromValue<qlonglong>(world.bytes());
     }
     case IconFileRole:
     {
@@ -301,7 +321,11 @@ public:
     }
 
 protected:
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    QVariant retrieveData(const QString &mimetype, QMetaType type) const
+#else
     QVariant retrieveData(const QString &mimetype, QVariant::Type type) const
+#endif
     {
         QList<QUrl> urls;
         for(auto &world: m_worlds)
diff --git a/launcher/minecraft/auth/AccountData.cpp b/launcher/minecraft/auth/AccountData.cpp
index 3c7b193c..44f7e256 100644
--- a/launcher/minecraft/auth/AccountData.cpp
+++ b/launcher/minecraft/auth/AccountData.cpp
@@ -39,6 +39,7 @@
 #include <QJsonArray>
 #include <QDebug>
 #include <QUuid>
+#include <QRegularExpression>
 
 namespace {
 void tokenToJSONV3(QJsonObject &parent, Katabasis::Token t, const char * tokenName) {
@@ -451,7 +452,7 @@ void AccountData::invalidateClientToken() {
     if(type != AccountType::Mojang) {
         return;
     }
-    yggdrasilToken.extra["clientToken"] = QUuid::createUuid().toString().remove(QRegExp("[{-}]"));
+    yggdrasilToken.extra["clientToken"] = QUuid::createUuid().toString().remove(QRegularExpression("[{-}]"));
 }
 
 QString AccountData::profileId() const {
diff --git a/launcher/minecraft/auth/AuthRequest.cpp b/launcher/minecraft/auth/AuthRequest.cpp
index feface80..bb82e1e2 100644
--- a/launcher/minecraft/auth/AuthRequest.cpp
+++ b/launcher/minecraft/auth/AuthRequest.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include <cassert>
 
 #include <QDebug>
@@ -20,7 +55,11 @@ void AuthRequest::get(const QNetworkRequest &req, int timeout/* = 60*1000*/) {
     reply_ = APPLICATION->network()->get(request_);
     status_ = Requesting;
     timedReplies_.add(new Katabasis::Reply(reply_, timeout));
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(reply_, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), this, SLOT(onRequestError(QNetworkReply::NetworkError)));
+#else
     connect(reply_, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(onRequestError(QNetworkReply::NetworkError)));
+#endif
     connect(reply_, SIGNAL(finished()), this, SLOT(onRequestFinished()));
     connect(reply_, &QNetworkReply::sslErrors, this, &AuthRequest::onSslErrors);
 }
@@ -31,7 +70,11 @@ void AuthRequest::post(const QNetworkRequest &req, const QByteArray &data, int t
     status_ = Requesting;
     reply_ = APPLICATION->network()->post(request_, data_);
     timedReplies_.add(new Katabasis::Reply(reply_, timeout));
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(reply_, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), this, SLOT(onRequestError(QNetworkReply::NetworkError)));
+#else
     connect(reply_, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(onRequestError(QNetworkReply::NetworkError)));
+#endif
     connect(reply_, SIGNAL(finished()), this, SLOT(onRequestFinished()));
     connect(reply_, &QNetworkReply::sslErrors, this, &AuthRequest::onSslErrors);
     connect(reply_, SIGNAL(uploadProgress(qint64,qint64)), this, SLOT(onUploadProgress(qint64,qint64)));
diff --git a/launcher/minecraft/auth/MinecraftAccount.cpp b/launcher/minecraft/auth/MinecraftAccount.cpp
index 9c8eb70b..a5c6f542 100644
--- a/launcher/minecraft/auth/MinecraftAccount.cpp
+++ b/launcher/minecraft/auth/MinecraftAccount.cpp
@@ -40,7 +40,7 @@
 #include <QUuid>
 #include <QJsonObject>
 #include <QJsonArray>
-#include <QRegExp>
+#include <QRegularExpression>
 #include <QStringList>
 #include <QJsonDocument>
 
@@ -53,7 +53,7 @@
 #include "flows/Offline.h"
 
 MinecraftAccount::MinecraftAccount(QObject* parent) : QObject(parent) {
-    data.internalId = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
+    data.internalId = QUuid::createUuid().toString().remove(QRegularExpression("[{}-]"));
 }
 
 
@@ -78,7 +78,7 @@ MinecraftAccountPtr MinecraftAccount::createFromUsername(const QString &username
     MinecraftAccountPtr account = new MinecraftAccount();
     account->data.type = AccountType::Mojang;
     account->data.yggdrasilToken.extra["userName"] = username;
-    account->data.yggdrasilToken.extra["clientToken"] = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
+    account->data.yggdrasilToken.extra["clientToken"] = QUuid::createUuid().toString().remove(QRegularExpression("[{}-]"));
     return account;
 }
 
@@ -97,10 +97,10 @@ MinecraftAccountPtr MinecraftAccount::createOffline(const QString &username)
     account->data.yggdrasilToken.validity = Katabasis::Validity::Certain;
     account->data.yggdrasilToken.issueInstant = QDateTime::currentDateTimeUtc();
     account->data.yggdrasilToken.extra["userName"] = username;
-    account->data.yggdrasilToken.extra["clientToken"] = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
+    account->data.yggdrasilToken.extra["clientToken"] = QUuid::createUuid().toString().remove(QRegularExpression("[{}-]"));
     account->data.minecraftEntitlement.ownsMinecraft = true;
     account->data.minecraftEntitlement.canPlayMinecraft = true;
-    account->data.minecraftProfile.id = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
+    account->data.minecraftProfile.id = QUuid::createUuid().toString().remove(QRegularExpression("[{}-]"));
     account->data.minecraftProfile.name = username;
     account->data.minecraftProfile.validity = Katabasis::Validity::Certain;
     return account;
diff --git a/launcher/minecraft/mod/ModFolderModel.cpp b/launcher/minecraft/mod/ModFolderModel.cpp
index bc2362a9..5ee08cbf 100644
--- a/launcher/minecraft/mod/ModFolderModel.cpp
+++ b/launcher/minecraft/mod/ModFolderModel.cpp
@@ -116,9 +116,17 @@ bool ModFolderModel::update()
 
 void ModFolderModel::finishUpdate()
 {
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    auto currentList = modsIndex.keys();
+    QSet<QString> currentSet(currentList.begin(), currentList.end());
+    auto & newMods = m_update->mods;
+    auto newList = newMods.keys();
+    QSet<QString> newSet(newList.begin(), newList.end());
+#else
     QSet<QString> currentSet = modsIndex.keys().toSet();
     auto & newMods = m_update->mods;
     QSet<QString> newSet = newMods.keys().toSet();
+#endif
 
     // see if the kept mods changed in some way
     {
@@ -309,7 +317,8 @@ bool ModFolderModel::installMod(const QString &filename)
             return false;
         }
         FS::updateTimestamp(newpath);
-        installedMod.repath(newpath);
+        QFileInfo newpathInfo(newpath);
+        installedMod.repath(newpathInfo);
         update();
         return true;
     }
@@ -327,7 +336,8 @@ bool ModFolderModel::installMod(const QString &filename)
             qWarning() << "Copy of folder from" << originalPath << "to" << newpath << "has (potentially partially) failed.";
             return false;
         }
-        installedMod.repath(newpath);
+        QFileInfo newpathInfo(newpath);
+        installedMod.repath(newpathInfo);
         update();
         return true;
     }
diff --git a/launcher/minecraft/services/CapeChange.cpp b/launcher/minecraft/services/CapeChange.cpp
index e49c166a..c73a11b6 100644
--- a/launcher/minecraft/services/CapeChange.cpp
+++ b/launcher/minecraft/services/CapeChange.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "CapeChange.h"
 
 #include <QNetworkRequest>
@@ -34,7 +69,11 @@ void CapeChange::clearCape() {
 
     m_reply = shared_qobject_ptr<QNetworkReply>(rep);
     connect(rep, &QNetworkReply::uploadProgress, this, &Task::setProgress);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(rep, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), this, SLOT(downloadError(QNetworkReply::NetworkError)));
+#else
     connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(downloadError(QNetworkReply::NetworkError)));
+#endif
     connect(rep, SIGNAL(finished()), this, SLOT(downloadFinished()));
 }
 
diff --git a/launcher/minecraft/services/SkinDelete.cpp b/launcher/minecraft/services/SkinDelete.cpp
index cce8364e..921bd094 100644
--- a/launcher/minecraft/services/SkinDelete.cpp
+++ b/launcher/minecraft/services/SkinDelete.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "SkinDelete.h"
 
 #include <QNetworkRequest>
@@ -19,7 +54,11 @@ void SkinDelete::executeTask()
 
     setStatus(tr("Deleting skin"));
     connect(rep, &QNetworkReply::uploadProgress, this, &Task::setProgress);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(rep, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), this, SLOT(downloadError(QNetworkReply::NetworkError)));
+#else
     connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(downloadError(QNetworkReply::NetworkError)));
+#endif
     connect(rep, SIGNAL(finished()), this, SLOT(downloadFinished()));
 }
 
diff --git a/launcher/minecraft/services/SkinUpload.cpp b/launcher/minecraft/services/SkinUpload.cpp
index 7c2e8337..c7987875 100644
--- a/launcher/minecraft/services/SkinUpload.cpp
+++ b/launcher/minecraft/services/SkinUpload.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "SkinUpload.h"
 
 #include <QNetworkRequest>
@@ -44,7 +79,11 @@ void SkinUpload::executeTask()
 
     setStatus(tr("Uploading skin"));
     connect(rep, &QNetworkReply::uploadProgress, this, &Task::setProgress);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(rep, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), this, SLOT(downloadError(QNetworkReply::NetworkError)));
+#else
     connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(downloadError(QNetworkReply::NetworkError)));
+#endif
     connect(rep, SIGNAL(finished()), this, SLOT(downloadFinished()));
 }
 
diff --git a/launcher/modplatform/ModAPI.h b/launcher/modplatform/ModAPI.h
index 91b760df..cf116353 100644
--- a/launcher/modplatform/ModAPI.h
+++ b/launcher/modplatform/ModAPI.h
@@ -1,7 +1,43 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 
 #include <QString>
 #include <QList>
+#include <list>
 
 #include "Version.h"
 
diff --git a/launcher/modplatform/atlauncher/ATLPackInstallTask.cpp b/launcher/modplatform/atlauncher/ATLPackInstallTask.cpp
index b8e0f4b0..0ed0ad29 100644
--- a/launcher/modplatform/atlauncher/ATLPackInstallTask.cpp
+++ b/launcher/modplatform/atlauncher/ATLPackInstallTask.cpp
@@ -36,7 +36,7 @@
 
 #include "ATLPackInstallTask.h"
 
-#include <QtConcurrent/QtConcurrent>
+#include <QtConcurrent>
 
 #include <quazip/quazip.h>
 
@@ -557,7 +557,11 @@ void PackInstallTask::extractConfigs()
         return;
     }
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    m_extractFuture = QtConcurrent::run(QThreadPool::globalInstance(), QOverload<QString, QString>::of(MMCZip::extractDir), archivePath, extractDir.absolutePath() + "/minecraft");
+#else
     m_extractFuture = QtConcurrent::run(QThreadPool::globalInstance(), MMCZip::extractDir, archivePath, extractDir.absolutePath() + "/minecraft");
+#endif
     connect(&m_extractFutureWatcher, &QFutureWatcher<QStringList>::finished, this, [&]()
     {
         downloadMods();
@@ -702,7 +706,11 @@ void PackInstallTask::onModsDownloaded() {
     jobPtr.reset();
 
     if(!modsToExtract.empty() || !modsToDecomp.empty() || !modsToCopy.empty()) {
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+        m_modExtractFuture = QtConcurrent::run(QThreadPool::globalInstance(), &PackInstallTask::extractMods, this, modsToExtract, modsToDecomp, modsToCopy);
+#else
         m_modExtractFuture = QtConcurrent::run(QThreadPool::globalInstance(), this, &PackInstallTask::extractMods, modsToExtract, modsToDecomp, modsToCopy);
+#endif
         connect(&m_modExtractFutureWatcher, &QFutureWatcher<QStringList>::finished, this, &PackInstallTask::onModsExtracted);
         connect(&m_modExtractFutureWatcher, &QFutureWatcher<QStringList>::canceled, this, [&]()
         {
@@ -754,7 +762,7 @@ bool PackInstallTask::extractMods(
         QString folderToExtract = "";
         if(mod.type == ModType::Extract) {
             folderToExtract = mod.extractFolder;
-            folderToExtract.remove(QRegExp("^/"));
+            folderToExtract.remove(QRegularExpression("^/"));
         }
 
         qDebug() << "Extracting " + mod.file + " to " + extractToDir;
diff --git a/launcher/modplatform/flame/PackManifest.h b/launcher/modplatform/flame/PackManifest.h
index 26a48d1c..677db1c3 100644
--- a/launcher/modplatform/flame/PackManifest.h
+++ b/launcher/modplatform/flame/PackManifest.h
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #pragma once
 
 #include <QString>
@@ -25,7 +60,7 @@ struct File
     bool resolved = false;
     QString fileName;
     QUrl url;
-    QString targetFolder = QLatin1Literal("mods");
+    QString targetFolder = QStringLiteral("mods");
     enum class Type
     {
         Unknown,
diff --git a/launcher/modplatform/legacy_ftb/PackFetchTask.cpp b/launcher/modplatform/legacy_ftb/PackFetchTask.cpp
index 961fe868..4da6a866 100644
--- a/launcher/modplatform/legacy_ftb/PackFetchTask.cpp
+++ b/launcher/modplatform/legacy_ftb/PackFetchTask.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "PackFetchTask.h"
 #include "PrivatePackManager.h"
 
@@ -103,7 +138,7 @@ bool PackFetchTask::parseAndAddPacks(QByteArray &data, PackType packType, Modpac
 
     if(!doc.setContent(data, false, &errorMsg, &errorLine, &errorCol))
     {
-        auto fullErrMsg = QString("Failed to fetch modpack data: %1 %2:3d!").arg(errorMsg, errorLine, errorCol);
+        auto fullErrMsg = QString("Failed to fetch modpack data: %1 %2:%3!").arg(errorMsg).arg(errorLine).arg(errorCol);
         qWarning() << fullErrMsg;
         data.clear();
         return false;
diff --git a/launcher/modplatform/legacy_ftb/PackInstallTask.cpp b/launcher/modplatform/legacy_ftb/PackInstallTask.cpp
index c63a9f1e..83e14969 100644
--- a/launcher/modplatform/legacy_ftb/PackInstallTask.cpp
+++ b/launcher/modplatform/legacy_ftb/PackInstallTask.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "PackInstallTask.h"
 
 #include <QtConcurrent>
@@ -88,7 +123,11 @@ void PackInstallTask::unzip()
         return;
     }
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    m_extractFuture = QtConcurrent::run(QThreadPool::globalInstance(), QOverload<QString, QString>::of(MMCZip::extractDir), archivePath, extractDir.absolutePath() + "/unzip");
+#else
     m_extractFuture = QtConcurrent::run(QThreadPool::globalInstance(), MMCZip::extractDir, archivePath, extractDir.absolutePath() + "/unzip");
+#endif
     connect(&m_extractFutureWatcher, &QFutureWatcher<QStringList>::finished, this, &PackInstallTask::onUnzipFinished);
     connect(&m_extractFutureWatcher, &QFutureWatcher<QStringList>::canceled, this, &PackInstallTask::onUnzipCanceled);
     m_extractFutureWatcher.setFuture(m_extractFuture);
diff --git a/launcher/modplatform/legacy_ftb/PrivatePackManager.cpp b/launcher/modplatform/legacy_ftb/PrivatePackManager.cpp
index 501e6003..1a81f026 100644
--- a/launcher/modplatform/legacy_ftb/PrivatePackManager.cpp
+++ b/launcher/modplatform/legacy_ftb/PrivatePackManager.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "PrivatePackManager.h"
 
 #include <QDebug>
@@ -10,7 +45,13 @@ void PrivatePackManager::load()
 {
     try
     {
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+        auto foo = QString::fromUtf8(FS::read(m_filename)).split('\n', Qt::SkipEmptyParts);
+        currentPacks = QSet<QString>(foo.begin(), foo.end());
+#else
         currentPacks = QString::fromUtf8(FS::read(m_filename)).split('\n', QString::SkipEmptyParts).toSet();
+#endif
+
         dirty = false;
     }
     catch(...)
@@ -28,7 +69,7 @@ void PrivatePackManager::save() const
     }
     try
     {
-        QStringList list = currentPacks.toList();
+        QStringList list = currentPacks.values();
         FS::write(m_filename, list.join('\n').toUtf8());
         dirty = false;
     }
diff --git a/launcher/net/Download.cpp b/launcher/net/Download.cpp
index d93eb088..3061e32e 100644
--- a/launcher/net/Download.cpp
+++ b/launcher/net/Download.cpp
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 flowln <flowlnlnln@gmail.com>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -126,7 +127,11 @@ void Download::executeTask()
     m_reply.reset(rep);
     connect(rep, &QNetworkReply::downloadProgress, this, &Download::downloadProgress);
     connect(rep, &QNetworkReply::finished, this, &Download::downloadFinished);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(rep, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
+#else
     connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
+#endif
     connect(rep, &QNetworkReply::sslErrors, this, &Download::sslErrors);
     connect(rep, &QNetworkReply::readyRead, this, &Download::downloadReadyRead);
 }
diff --git a/launcher/net/NetJob.cpp b/launcher/net/NetJob.cpp
index df899178..bab35fa5 100644
--- a/launcher/net/NetJob.cpp
+++ b/launcher/net/NetJob.cpp
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 flowln <flowlnlnln@gmail.com>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -97,11 +98,16 @@ auto NetJob::abort() -> bool
     bool fullyAborted = true;
 
     // fail all downloads on the queue
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    QSet<int> todoSet(m_todo.begin(), m_todo.end());
+    m_failed.unite(todoSet);
+#else
     m_failed.unite(m_todo.toSet());
+#endif
     m_todo.clear();
 
     // abort active downloads
-    auto toKill = m_doing.toList();
+    auto toKill = m_doing.values();
     for (auto index : toKill) {
         auto part = m_downloads[index];
         fullyAborted &= part->abort();
diff --git a/launcher/net/PasteUpload.cpp b/launcher/net/PasteUpload.cpp
index 835e4cd1..76b86743 100644
--- a/launcher/net/PasteUpload.cpp
+++ b/launcher/net/PasteUpload.cpp
@@ -129,10 +129,13 @@ void PasteUpload::executeTask()
 
     connect(rep, &QNetworkReply::uploadProgress, this, &Task::setProgress);
     connect(rep, &QNetworkReply::finished, this, &PasteUpload::downloadFinished);
-    // This function call would be a lot shorter if we were using the latest Qt
-    connect(rep,
-            static_cast<void (QNetworkReply::*)(QNetworkReply::NetworkError)>(&QNetworkReply::error),
-            this, &PasteUpload::downloadError);
+
+#if QT_VERSION >= QT_VERSION_CHECK(5, 15, 0)
+    connect(rep, &QNetworkReply::errorOccurred, this, &PasteUpload::downloadError);
+#else
+    connect(rep, QOverload<QNetworkReply::NetworkError>::of(&QNetworkReply::error), this, &PasteUpload::downloadError);
+#endif
+
 
     m_reply = std::shared_ptr<QNetworkReply>(rep);
 
diff --git a/launcher/news/NewsChecker.cpp b/launcher/news/NewsChecker.cpp
index 6724950f..3b969732 100644
--- a/launcher/news/NewsChecker.cpp
+++ b/launcher/news/NewsChecker.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "NewsChecker.h"
@@ -61,7 +81,7 @@ void NewsChecker::rssDownloadFinished()
         // Parse the XML.
         if (!doc.setContent(newsData, false, &errorMsg, &errorLine, &errorCol))
         {
-            QString fullErrorMsg = QString("Error parsing RSS feed XML. %s at %d:%d.").arg(errorMsg, errorLine, errorCol);
+            QString fullErrorMsg = QString("Error parsing RSS feed XML. %1 at %2:%3.").arg(errorMsg).arg(errorLine).arg(errorCol);
             fail(fullErrorMsg);
             newsData.clear();
             return;
diff --git a/launcher/screenshots/ImgurAlbumCreation.cpp b/launcher/screenshots/ImgurAlbumCreation.cpp
index 04e26ea2..a72c32d3 100644
--- a/launcher/screenshots/ImgurAlbumCreation.cpp
+++ b/launcher/screenshots/ImgurAlbumCreation.cpp
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 flowln <flowlnlnln@gmail.com>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -73,7 +74,11 @@ void ImgurAlbumCreation::executeTask()
     m_reply.reset(rep);
     connect(rep, &QNetworkReply::uploadProgress, this, &ImgurAlbumCreation::downloadProgress);
     connect(rep, &QNetworkReply::finished, this, &ImgurAlbumCreation::downloadFinished);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(rep, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
+#else
     connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
+#endif
 }
 void ImgurAlbumCreation::downloadError(QNetworkReply::NetworkError error)
 {
diff --git a/launcher/screenshots/ImgurUpload.cpp b/launcher/screenshots/ImgurUpload.cpp
index 9aeb6fb8..f8ac9bc2 100644
--- a/launcher/screenshots/ImgurUpload.cpp
+++ b/launcher/screenshots/ImgurUpload.cpp
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 flowln <flowlnlnln@gmail.com>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -88,8 +89,11 @@ void ImgurUpload::executeTask()
     m_reply.reset(rep);
     connect(rep, &QNetworkReply::uploadProgress, this, &ImgurUpload::downloadProgress);
     connect(rep, &QNetworkReply::finished, this, &ImgurUpload::downloadFinished);
-    connect(rep, SIGNAL(error(QNetworkReply::NetworkError)),
-            SLOT(downloadError(QNetworkReply::NetworkError)));
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    connect(rep, SIGNAL(errorOccurred(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
+#else
+    connect(rep, SIGNAL(error(QNetworkReply::NetworkError)), SLOT(downloadError(QNetworkReply::NetworkError)));
+#endif
 }
 void ImgurUpload::downloadError(QNetworkReply::NetworkError error)
 {
diff --git a/launcher/settings/INIFile.cpp b/launcher/settings/INIFile.cpp
index 6a3c801d..733cd444 100644
--- a/launcher/settings/INIFile.cpp
+++ b/launcher/settings/INIFile.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "settings/INIFile.h"
@@ -29,7 +49,7 @@ INIFile::INIFile()
 QString INIFile::unescape(QString orig)
 {
     QString out;
-    QChar prev = 0;
+    QChar prev = QChar::Null;
     for(auto c: orig)
     {
         if(prev == '\\')
@@ -42,7 +62,7 @@ QString INIFile::unescape(QString orig)
                 out += '#';
             else
                 out += c;
-            prev = 0;
+            prev = QChar::Null;
         }
         else
         {
@@ -52,7 +72,7 @@ QString INIFile::unescape(QString orig)
                 continue;
             }
             out += c;
-            prev = 0;
+            prev = QChar::Null;
         }
     }
     return out;
@@ -117,7 +137,9 @@ bool INIFile::loadFile(QString fileName)
 bool INIFile::loadFile(QByteArray file)
 {
     QTextStream in(file);
+#if QT_VERSION <= QT_VERSION_CHECK(6, 0, 0)
     in.setCodec("UTF-8");
+#endif
 
     QStringList lines = in.readAll().split('\n');
     for (int i = 0; i < lines.count(); i++)
diff --git a/launcher/translations/TranslationsModel.cpp b/launcher/translations/TranslationsModel.cpp
index 53722d69..848b4d19 100644
--- a/launcher/translations/TranslationsModel.cpp
+++ b/launcher/translations/TranslationsModel.cpp
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 flowln <flowlnlnln@gmail.com>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -52,7 +53,7 @@
 
 #include "Application.h"
 
-const static QLatin1Literal defaultLangCode("en_US");
+const static QLatin1String defaultLangCode("en_US");
 
 enum class FileType
 {
@@ -431,9 +432,7 @@ QVariant TranslationsModel::data(const QModelIndex& index, int role) const
             }
             case Column::Completeness:
             {
-                QString text;
-                text.sprintf("%3.1f %%", lang.percentTranslated());
-                return text;
+                return QString("%1%").arg(lang.percentTranslated(), 3, 'f', 1);
             }
         }
     }
diff --git a/launcher/ui/InstanceWindow.cpp b/launcher/ui/InstanceWindow.cpp
index ae765c3c..0ad8c594 100644
--- a/launcher/ui/InstanceWindow.cpp
+++ b/launcher/ui/InstanceWindow.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "InstanceWindow.h"
@@ -97,9 +117,9 @@ InstanceWindow::InstanceWindow(InstancePtr instance, QWidget *parent)
     // set up instance and launch process recognition
     {
         auto launchTask = m_instance->getLaunchTask();
-        on_InstanceLaunchTask_changed(launchTask);
-        connect(m_instance.get(), &BaseInstance::launchTaskChanged, this, &InstanceWindow::on_InstanceLaunchTask_changed);
-        connect(m_instance.get(), &BaseInstance::runningStatusChanged, this, &InstanceWindow::on_RunningState_changed);
+        instanceLaunchTaskChanged(launchTask);
+        connect(m_instance.get(), &BaseInstance::launchTaskChanged, this, &InstanceWindow::instanceLaunchTaskChanged);
+        connect(m_instance.get(), &BaseInstance::runningStatusChanged, this, &InstanceWindow::runningStateChanged);
     }
 
     // set up instance destruction detection
@@ -152,12 +172,12 @@ void InstanceWindow::on_btnLaunchMinecraftOffline_clicked()
     APPLICATION->launch(m_instance, false, nullptr);
 }
 
-void InstanceWindow::on_InstanceLaunchTask_changed(shared_qobject_ptr<LaunchTask> proc)
+void InstanceWindow::instanceLaunchTaskChanged(shared_qobject_ptr<LaunchTask> proc)
 {
     m_proc = proc;
 }
 
-void InstanceWindow::on_RunningState_changed(bool running)
+void InstanceWindow::runningStateChanged(bool running)
 {
     updateLaunchButtons();
     m_container->refreshContainer();
diff --git a/launcher/ui/InstanceWindow.h b/launcher/ui/InstanceWindow.h
index 1acf684e..aec07868 100644
--- a/launcher/ui/InstanceWindow.h
+++ b/launcher/ui/InstanceWindow.h
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #pragma once
@@ -55,8 +75,8 @@ slots:
     void on_btnKillMinecraft_clicked();
     void on_btnLaunchMinecraftOffline_clicked();
 
-    void on_InstanceLaunchTask_changed(shared_qobject_ptr<LaunchTask> proc);
-    void on_RunningState_changed(bool running);
+    void instanceLaunchTaskChanged(shared_qobject_ptr<LaunchTask> proc);
+    void runningStateChanged(bool running);
     void on_instanceStatusChanged(BaseInstance::Status, BaseInstance::Status newStatus);
 
 protected:
diff --git a/launcher/ui/MainWindow.cpp b/launcher/ui/MainWindow.cpp
index aeff8073..d107635e 100644
--- a/launcher/ui/MainWindow.cpp
+++ b/launcher/ui/MainWindow.cpp
@@ -42,31 +42,31 @@
 
 #include "MainWindow.h"
 
-#include <QtCore/QVariant>
-#include <QtCore/QUrl>
-#include <QtCore/QDir>
-#include <QtCore/QFileInfo>
-
-#include <QtGui/QKeyEvent>
-
-#include <QtWidgets/QAction>
-#include <QtWidgets/QApplication>
-#include <QtWidgets/QButtonGroup>
-#include <QtWidgets/QHBoxLayout>
-#include <QtWidgets/QHeaderView>
-#include <QtWidgets/QMainWindow>
-#include <QtWidgets/QStatusBar>
-#include <QtWidgets/QToolBar>
-#include <QtWidgets/QWidget>
-#include <QtWidgets/QMenu>
-#include <QtWidgets/QMenuBar>
-#include <QtWidgets/QMessageBox>
-#include <QtWidgets/QInputDialog>
-#include <QtWidgets/QLabel>
-#include <QtWidgets/QToolButton>
-#include <QtWidgets/QWidgetAction>
-#include <QtWidgets/QProgressDialog>
-#include <QtWidgets/QShortcut>
+#include <QVariant>
+#include <QUrl>
+#include <QDir>
+#include <QFileInfo>
+
+#include <QKeyEvent>
+#include <QAction>
+
+#include <QApplication>
+#include <QButtonGroup>
+#include <QHBoxLayout>
+#include <QHeaderView>
+#include <QMainWindow>
+#include <QStatusBar>
+#include <QToolBar>
+#include <QWidget>
+#include <QMenu>
+#include <QMenuBar>
+#include <QMessageBox>
+#include <QInputDialog>
+#include <QLabel>
+#include <QToolButton>
+#include <QWidgetAction>
+#include <QProgressDialog>
+#include <QShortcut>
 
 #include <BaseInstance.h>
 #include <InstanceList.h>
@@ -235,7 +235,6 @@ public:
     TranslatedAction actionMods;
     TranslatedAction actionViewSelectedInstFolder;
     TranslatedAction actionViewSelectedMCFolder;
-    TranslatedAction actionViewSelectedModsFolder;
     TranslatedAction actionDeleteInstance;
     TranslatedAction actionConfig_Folder;
     TranslatedAction actionCAT;
@@ -709,14 +708,6 @@ public:
         actionViewSelectedMCFolder->setShortcut(QKeySequence(tr("Ctrl+M")));
         all_actions.append(&actionViewSelectedMCFolder);
 
-        /*
-        actionViewSelectedModsFolder = TranslatedAction(MainWindow);
-        actionViewSelectedModsFolder->setObjectName(QStringLiteral("actionViewSelectedModsFolder"));
-        actionViewSelectedModsFolder.setTextId(QT_TRANSLATE_NOOP("MainWindow", "Mods Folder"));
-        actionViewSelectedModsFolder.setTooltipId(QT_TRANSLATE_NOOP("MainWindow", "Open the selected instance's mods folder in a file browser."));
-        all_actions.append(&actionViewSelectedModsFolder);
-        */
-
         actionConfig_Folder = TranslatedAction(MainWindow);
         actionConfig_Folder->setObjectName(QStringLiteral("actionConfig_Folder"));
         actionConfig_Folder.setTextId(QT_TRANSLATE_NOOP("MainWindow", "Confi&g Folder"));
@@ -793,9 +784,6 @@ public:
         instanceToolBar->addSeparator();
 
         instanceToolBar->addAction(actionViewSelectedMCFolder);
-        /*
-        instanceToolBar->addAction(actionViewSelectedModsFolder);
-        */
         instanceToolBar->addAction(actionConfig_Folder);
         instanceToolBar->addAction(actionViewSelectedInstFolder);
 
@@ -1494,7 +1482,11 @@ void MainWindow::updateNotAvailable()
 
 QList<int> stringToIntList(const QString &string)
 {
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    QStringList split = string.split(',', Qt::SkipEmptyParts);
+#else
     QStringList split = string.split(',', QString::SkipEmptyParts);
+#endif
     QList<int> out;
     for (int i = 0; i < split.size(); ++i)
     {
@@ -1890,11 +1882,6 @@ void MainWindow::globalSettingsClosed()
     update();
 }
 
-void MainWindow::on_actionInstanceSettings_triggered()
-{
-    APPLICATION->showInstanceWindow(m_selectedInstance, "settings");
-}
-
 void MainWindow::on_actionEditInstNotes_triggered()
 {
     APPLICATION->showInstanceWindow(m_selectedInstance, "notes");
@@ -2017,20 +2004,6 @@ void MainWindow::on_actionViewSelectedMCFolder_triggered()
     }
 }
 
-void MainWindow::on_actionViewSelectedModsFolder_triggered()
-{
-    if (m_selectedInstance)
-    {
-        QString str = m_selectedInstance->modsRoot();
-        if (!FS::ensureFilePathExists(str))
-        {
-            // TODO: report error
-            return;
-        }
-        DesktopServices::openDirectory(QDir(str).absolutePath());
-    }
-}
-
 void MainWindow::closeEvent(QCloseEvent *event)
 {
     // Save the window state and geometry.
diff --git a/launcher/ui/MainWindow.h b/launcher/ui/MainWindow.h
index 0ca8ec7b..d7930b5a 100644
--- a/launcher/ui/MainWindow.h
+++ b/launcher/ui/MainWindow.h
@@ -118,8 +118,6 @@ private slots:
 
     void on_actionViewSelectedMCFolder_triggered();
 
-    void on_actionViewSelectedModsFolder_triggered();
-
     void refreshInstances();
 
     void on_actionViewCentralModsFolder_triggered();
@@ -128,8 +126,6 @@ private slots:
 
     void on_actionSettings_triggered();
 
-    void on_actionInstanceSettings_triggered();
-
     void on_actionManageAccounts_triggered();
 
     void on_actionReportBug_triggered();
diff --git a/launcher/ui/dialogs/AboutDialog.cpp b/launcher/ui/dialogs/AboutDialog.cpp
index 8dadb755..c5367d5b 100644
--- a/launcher/ui/dialogs/AboutDialog.cpp
+++ b/launcher/ui/dialogs/AboutDialog.cpp
@@ -64,7 +64,9 @@ QString getCreditsHtml()
 {
     QString output;
     QTextStream stream(&output);
+#if QT_VERSION <= QT_VERSION_CHECK(6, 0, 0)
     stream.setCodec(QTextCodec::codecForName("UTF-8"));
+#endif
     stream << "<center>\n";
 
     //: %1 is the name of the launcher, determined at build time, e.g. "PolyMC Developers"
diff --git a/launcher/ui/dialogs/CopyInstanceDialog.cpp b/launcher/ui/dialogs/CopyInstanceDialog.cpp
index e5113981..9ec341bc 100644
--- a/launcher/ui/dialogs/CopyInstanceDialog.cpp
+++ b/launcher/ui/dialogs/CopyInstanceDialog.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QLayout>
@@ -39,8 +59,14 @@ CopyInstanceDialog::CopyInstanceDialog(InstancePtr original, QWidget *parent)
     ui->iconButton->setIcon(APPLICATION->icons()->getIcon(InstIconKey));
     ui->instNameTextBox->setText(original->name());
     ui->instNameTextBox->setFocus();
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    auto groupList = APPLICATION->instances()->getGroups();
+    QSet<QString> groups(groupList.begin(), groupList.end());
+    groupList = QStringList(groups.values());
+#else
     auto groups = APPLICATION->instances()->getGroups().toSet();
     auto groupList = QStringList(groups.toList());
+#endif
     groupList.sort(Qt::CaseInsensitive);
     groupList.removeOne("");
     groupList.push_front("");
diff --git a/launcher/ui/dialogs/ExportInstanceDialog.cpp b/launcher/ui/dialogs/ExportInstanceDialog.cpp
index 8631edf6..9f32dd8e 100644
--- a/launcher/ui/dialogs/ExportInstanceDialog.cpp
+++ b/launcher/ui/dialogs/ExportInstanceDialog.cpp
@@ -488,7 +488,11 @@ void ExportInstanceDialog::loadPackIgnore()
     }
     auto data = ignoreFile.readAll();
     auto string = QString::fromUtf8(data);
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    proxyModel->setBlockedPaths(string.split('\n', Qt::SkipEmptyParts));
+#else
     proxyModel->setBlockedPaths(string.split('\n', QString::SkipEmptyParts));
+#endif
 }
 
 void ExportInstanceDialog::savePackIgnore()
diff --git a/launcher/ui/dialogs/NewComponentDialog.cpp b/launcher/ui/dialogs/NewComponentDialog.cpp
index 1bbafb0c..ea790e8c 100644
--- a/launcher/ui/dialogs/NewComponentDialog.cpp
+++ b/launcher/ui/dialogs/NewComponentDialog.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "Application.h"
@@ -46,7 +66,6 @@ NewComponentDialog::NewComponentDialog(const QString & initialName, const QStrin
     connect(ui->nameTextBox, &QLineEdit::textChanged, this, &NewComponentDialog::updateDialogState);
     connect(ui->uidTextBox, &QLineEdit::textChanged, this, &NewComponentDialog::updateDialogState);
 
-    auto groups = APPLICATION->instances()->getGroups().toSet();
     ui->nameTextBox->setFocus();
 
     originalPlaceholderText = ui->uidTextBox->placeholderText();
diff --git a/launcher/ui/dialogs/NewInstanceDialog.cpp b/launcher/ui/dialogs/NewInstanceDialog.cpp
index 05ea091d..5b8ecc5b 100644
--- a/launcher/ui/dialogs/NewInstanceDialog.cpp
+++ b/launcher/ui/dialogs/NewInstanceDialog.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "Application.h"
@@ -54,8 +74,14 @@ NewInstanceDialog::NewInstanceDialog(const QString & initialGroup, const QString
     InstIconKey = "default";
     ui->iconButton->setIcon(APPLICATION->icons()->getIcon(InstIconKey));
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    auto groupList = APPLICATION->instances()->getGroups();
+    auto groups = QSet<QString>(groupList.begin(), groupList.end());
+    groupList = groups.values();
+#else
     auto groups = APPLICATION->instances()->getGroups().toSet();
     auto groupList = QStringList(groups.toList());
+#endif
     groupList.sort(Qt::CaseInsensitive);
     groupList.removeOne("");
     groupList.push_front(initialGroup);
diff --git a/launcher/ui/dialogs/NewsDialog.cpp b/launcher/ui/dialogs/NewsDialog.cpp
index df620464..d3b21627 100644
--- a/launcher/ui/dialogs/NewsDialog.cpp
+++ b/launcher/ui/dialogs/NewsDialog.cpp
@@ -16,7 +16,7 @@ NewsDialog::NewsDialog(QList<NewsEntryPtr> entries, QWidget* parent) : QDialog(p
     m_article_list_hidden = ui->articleListWidget->isHidden();
 
     auto first_item = ui->articleListWidget->item(0);
-    ui->articleListWidget->setItemSelected(first_item, true);
+    first_item->setSelected(true);
 
     auto article_entry = m_entries.constFind(first_item->text()).value();
     ui->articleTitleLabel->setText(QString("<a href='%1'>%2</a>").arg(article_entry->link, first_item->text()));
diff --git a/launcher/ui/dialogs/ProfileSetupDialog.cpp b/launcher/ui/dialogs/ProfileSetupDialog.cpp
index 76b6af49..64c0b924 100644
--- a/launcher/ui/dialogs/ProfileSetupDialog.cpp
+++ b/launcher/ui/dialogs/ProfileSetupDialog.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "ProfileSetupDialog.h"
@@ -18,7 +38,7 @@
 
 #include <QPushButton>
 #include <QAction>
-#include <QRegExpValidator>
+#include <QRegularExpressionValidator>
 #include <QJsonDocument>
 #include <QDebug>
 
@@ -39,9 +59,9 @@ ProfileSetupDialog::ProfileSetupDialog(MinecraftAccountPtr accountToSetup, QWidg
     yellowIcon = APPLICATION->getThemedIcon("status-yellow");
     badIcon = APPLICATION->getThemedIcon("status-bad");
 
-    QRegExp permittedNames("[a-zA-Z0-9_]{3,16}");
+    QRegularExpression permittedNames("[a-zA-Z0-9_]{3,16}");
     auto nameEdit = ui->nameEdit;
-    nameEdit->setValidator(new QRegExpValidator(permittedNames));
+    nameEdit->setValidator(new QRegularExpressionValidator(permittedNames));
     nameEdit->setClearButtonEnabled(true);
     validityAction = nameEdit->addAction(yellowIcon, QLineEdit::LeadingPosition);
     connect(nameEdit, &QLineEdit::textEdited, this, &ProfileSetupDialog::nameEdited);
diff --git a/launcher/ui/dialogs/SkinUploadDialog.cpp b/launcher/ui/dialogs/SkinUploadDialog.cpp
index 8d137afc..b5b78690 100644
--- a/launcher/ui/dialogs/SkinUploadDialog.cpp
+++ b/launcher/ui/dialogs/SkinUploadDialog.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include <QFileInfo>
 #include <QFileDialog>
 #include <QPainter>
@@ -22,10 +57,10 @@ void SkinUploadDialog::on_buttonBox_accepted()
 {
     QString fileName;
     QString input = ui->skinPathTextBox->text();
-    QRegExp urlPrefixMatcher("^([a-z]+)://.+$");
+    QRegularExpression urlPrefixMatcher(QRegularExpression::anchoredPattern("^([a-z]+)://.+$"));
     bool isLocalFile = false;
     // it has an URL prefix -> it is an URL
-    if(urlPrefixMatcher.exactMatch(input))
+    if(urlPrefixMatcher.match(input).hasMatch())
     {
         QUrl fileURL = input;
         if(fileURL.isValid())
diff --git a/launcher/ui/dialogs/UpdateDialog.cpp b/launcher/ui/dialogs/UpdateDialog.cpp
index ec77d146..e0c5a495 100644
--- a/launcher/ui/dialogs/UpdateDialog.cpp
+++ b/launcher/ui/dialogs/UpdateDialog.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "UpdateDialog.h"
 #include "ui_UpdateDialog.h"
 #include <QDebug>
@@ -58,7 +93,7 @@ QString reprocessMarkdown(QByteArray markdown)
     QString output = hoedown.process(markdown);
 
     // HACK: easier than customizing hoedown
-    output.replace(QRegExp("GH-([0-9]+)"), "<a href=\"https://github.com/PolyMC/PolyMC/issues/\\1\">GH-\\1</a>");
+    output.replace(QRegularExpression("GH-([0-9]+)"), "<a href=\"https://github.com/PolyMC/PolyMC/issues/\\1\">GH-\\1</a>");
     qDebug() << output;
     return output;
 }
diff --git a/launcher/ui/instanceview/InstanceDelegate.cpp b/launcher/ui/instanceview/InstanceDelegate.cpp
index b446e39d..137cc8d5 100644
--- a/launcher/ui/instanceview/InstanceDelegate.cpp
+++ b/launcher/ui/instanceview/InstanceDelegate.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "InstanceDelegate.h"
@@ -24,7 +44,7 @@
 #include "InstanceView.h"
 #include "BaseInstance.h"
 #include "InstanceList.h"
-#include <xdgicon.h>
+#include <QIcon>
 #include <QTextEdit>
 
 // Origin: Qt
@@ -61,7 +81,7 @@ void drawSelectionRect(QPainter *painter, const QStyleOptionViewItem &option,
         painter->fillRect(rect, option.palette.brush(QPalette::Highlight));
     else
     {
-        QColor backgroundColor = option.palette.color(QPalette::Background);
+        QColor backgroundColor = option.palette.color(QPalette::Window);
         backgroundColor.setAlpha(160);
         painter->fillRect(rect, QBrush(backgroundColor));
     }
@@ -142,7 +162,7 @@ void drawBadges(QPainter *painter, const QStyleOptionViewItem &option, BaseInsta
                 return;
             }
             // FIXME: inject this.
-            auto icon = XdgIcon::fromTheme(it.next());
+            auto icon = QIcon::fromTheme(it.next());
             // opt.icon.paint(painter, iconbox, Qt::AlignCenter, mode, state);
             const QPixmap pixmap;
             // itemSide
diff --git a/launcher/ui/instanceview/InstanceView.cpp b/launcher/ui/instanceview/InstanceView.cpp
index 25aec1ab..fbeffe35 100644
--- a/launcher/ui/instanceview/InstanceView.cpp
+++ b/launcher/ui/instanceview/InstanceView.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "InstanceView.h"
@@ -425,7 +445,12 @@ void InstanceView::mouseReleaseEvent(QMouseEvent *event)
         {
             emit clicked(index);
         }
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+        QStyleOptionViewItem option;
+        initViewItemOption(&option);
+#else
         QStyleOptionViewItem option = viewOptions();
+#endif
         if (m_pressedAlreadySelected)
         {
             option.state |= QStyle::State_Selected;
@@ -461,7 +486,12 @@ void InstanceView::mouseDoubleClickEvent(QMouseEvent *event)
     QPersistentModelIndex persistent = index;
     emit doubleClicked(persistent);
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    QStyleOptionViewItem option;
+    initViewItemOption(&option);
+#else
     QStyleOptionViewItem option = viewOptions();
+#endif
     if ((model()->flags(index) & Qt::ItemIsEnabled) && !style()->styleHint(QStyle::SH_ItemView_ActivateItemOnSingleClick, &option, this))
     {
         emit activated(index);
@@ -474,7 +504,12 @@ void InstanceView::paintEvent(QPaintEvent *event)
 
     QPainter painter(this->viewport());
 
-    QStyleOptionViewItem option(viewOptions());
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    QStyleOptionViewItem option;
+    initViewItemOption(&option);
+#else
+    QStyleOptionViewItem option = viewOptions();
+#endif
     option.widget = this;
 
     int wpWidth = viewport()->width();
@@ -528,9 +563,9 @@ void InstanceView::paintEvent(QPaintEvent *event)
 #if 0
     if (!m_lastDragPosition.isNull())
     {
-        QPair<Group *, int> pair = rowDropPos(m_lastDragPosition);
-        Group *category = pair.first;
-        int row = pair.second;
+        std::pair<VisualGroup *, VisualGroup::HitResults> pair = rowDropPos(m_lastDragPosition);
+        VisualGroup *category = pair.first;
+        VisualGroup::HitResults row = pair.second;
         if (category)
         {
             int internalRow = row - category->firstItemIndex;
@@ -618,7 +653,7 @@ void InstanceView::dropEvent(QDropEvent *event)
     {
         if(event->possibleActions() & Qt::MoveAction)
         {
-            QPair<VisualGroup *, VisualGroup::HitResults> dropPos = rowDropPos(event->pos());
+            std::pair<VisualGroup *, VisualGroup::HitResults> dropPos = rowDropPos(event->pos());
             const VisualGroup *group = dropPos.first;
             auto hitresult = dropPos.second;
 
@@ -709,10 +744,18 @@ QRect InstanceView::geometryRect(const QModelIndex &index) const
     int x = pos.first;
     // int y = pos.second;
 
+
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    QStyleOptionViewItem option;
+    initViewItemOption(&option);
+#else
+    QStyleOptionViewItem option = viewOptions();
+#endif
+
     QRect out;
     out.setTop(cat->verticalPosition() + cat->headerHeight() + 5 + cat->rowTopOf(index));
     out.setLeft(m_spacing + x * (itemWidth() + m_spacing));
-    out.setSize(itemDelegate()->sizeHint(viewOptions(), index));
+    out.setSize(itemDelegate()->sizeHint(option, index));
     geometryCache.insert(row, new QRect(out));
     return out;
 }
@@ -759,7 +802,12 @@ QPixmap InstanceView::renderToPixmap(const QModelIndexList &indices, QRect *r) c
     QPixmap pixmap(r->size());
     pixmap.fill(Qt::transparent);
     QPainter painter(&pixmap);
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    QStyleOptionViewItem option;
+    initViewItemOption(&option);
+#else
     QStyleOptionViewItem option = viewOptions();
+#endif
     option.state |= QStyle::State_Selected;
     for (int j = 0; j < paintPairs.count(); ++j)
     {
@@ -770,16 +818,16 @@ QPixmap InstanceView::renderToPixmap(const QModelIndexList &indices, QRect *r) c
     return pixmap;
 }
 
-QList<QPair<QRect, QModelIndex>> InstanceView::draggablePaintPairs(const QModelIndexList &indices, QRect *r) const
+QList<std::pair<QRect, QModelIndex>> InstanceView::draggablePaintPairs(const QModelIndexList &indices, QRect *r) const
 {
     Q_ASSERT(r);
     QRect &rect = *r;
-    QList<QPair<QRect, QModelIndex>> ret;
+    QList<std::pair<QRect, QModelIndex>> ret;
     for (int i = 0; i < indices.count(); ++i)
     {
         const QModelIndex &index = indices.at(i);
         const QRect current = geometryRect(index);
-        ret += qMakePair(current, index);
+        ret += std::make_pair(current, index);
         rect |= current;
     }
     return ret;
@@ -790,11 +838,11 @@ bool InstanceView::isDragEventAccepted(QDropEvent *event)
     return true;
 }
 
-QPair<VisualGroup *, VisualGroup::HitResults> InstanceView::rowDropPos(const QPoint &pos)
+std::pair<VisualGroup *, VisualGroup::HitResults> InstanceView::rowDropPos(const QPoint &pos)
 {
     VisualGroup::HitResults hitresult;
     auto group = categoryAt(pos + offset(), hitresult);
-    return qMakePair<VisualGroup*, int>(group, hitresult);
+    return std::make_pair(group, hitresult);
 }
 
 QPoint InstanceView::offset() const
diff --git a/launcher/ui/instanceview/InstanceView.h b/launcher/ui/instanceview/InstanceView.h
index 406362e6..ac338274 100644
--- a/launcher/ui/instanceview/InstanceView.h
+++ b/launcher/ui/instanceview/InstanceView.h
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #pragma once
@@ -143,11 +163,11 @@ private: /* methods */
     int calculateItemsPerRow() const;
     int verticalScrollToValue(const QModelIndex &index, const QRect &rect, QListView::ScrollHint hint) const;
     QPixmap renderToPixmap(const QModelIndexList &indices, QRect *r) const;
-    QList<QPair<QRect, QModelIndex>> draggablePaintPairs(const QModelIndexList &indices, QRect *r) const;
+    QList<std::pair<QRect, QModelIndex>> draggablePaintPairs(const QModelIndexList &indices, QRect *r) const;
 
     bool isDragEventAccepted(QDropEvent *event);
 
-    QPair<VisualGroup *, VisualGroup::HitResults> rowDropPos(const QPoint &pos);
+    std::pair<VisualGroup *, VisualGroup::HitResults> rowDropPos(const QPoint &pos);
 
     QPoint offset() const;
 };
diff --git a/launcher/ui/instanceview/VisualGroup.cpp b/launcher/ui/instanceview/VisualGroup.cpp
index 8991fb2d..e6bca17d 100644
--- a/launcher/ui/instanceview/VisualGroup.cpp
+++ b/launcher/ui/instanceview/VisualGroup.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include "VisualGroup.h"
@@ -55,7 +75,14 @@ void VisualGroup::update()
             positionInRow = 0;
             maxRowHeight = 0;
         }
-        auto itemHeight = view->itemDelegate()->sizeHint(view->viewOptions(), item).height();
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+        QStyleOptionViewItem viewItemOption;
+        view->initViewItemOption(&viewItemOption);
+#else
+        QStyleOptionViewItem viewItemOption = view->viewOptions();
+#endif
+
+        auto itemHeight = view->itemDelegate()->sizeHint(viewItemOption, item).height();
         if(itemHeight > maxRowHeight)
         {
             maxRowHeight = itemHeight;
diff --git a/launcher/ui/pages/global/CustomCommandsPage.cpp b/launcher/ui/pages/global/CustomCommandsPage.cpp
index 436d766e..df1420ca 100644
--- a/launcher/ui/pages/global/CustomCommandsPage.cpp
+++ b/launcher/ui/pages/global/CustomCommandsPage.cpp
@@ -2,7 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/global/ProxyPage.cpp b/launcher/ui/pages/global/ProxyPage.cpp
index aefd1e74..ffff8456 100644
--- a/launcher/ui/pages/global/ProxyPage.cpp
+++ b/launcher/ui/pages/global/ProxyPage.cpp
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -36,11 +37,11 @@
 #include "ProxyPage.h"
 #include "ui_ProxyPage.h"
 
+#include <QButtonGroup>
 #include <QTabBar>
 
 #include "settings/SettingsObject.h"
 #include "Application.h"
-#include "Application.h"
 
 ProxyPage::ProxyPage(QWidget *parent) : QWidget(parent), ui(new Ui::ProxyPage)
 {
@@ -49,7 +50,8 @@ ProxyPage::ProxyPage(QWidget *parent) : QWidget(parent), ui(new Ui::ProxyPage)
     loadSettings();
     updateCheckboxStuff();
 
-    connect(ui->proxyGroup, SIGNAL(buttonClicked(int)), SLOT(proxyChanged(int)));
+    connect(ui->proxyGroup, QOverload<QAbstractButton *>::of(&QButtonGroup::buttonClicked),
+            this, &ProxyPage::proxyGroupChanged);
 }
 
 ProxyPage::~ProxyPage()
@@ -65,13 +67,13 @@ bool ProxyPage::apply()
 
 void ProxyPage::updateCheckboxStuff()
 {
-    ui->proxyAddrBox->setEnabled(!ui->proxyNoneBtn->isChecked() &&
-                                 !ui->proxyDefaultBtn->isChecked());
-    ui->proxyAuthBox->setEnabled(!ui->proxyNoneBtn->isChecked() &&
-                                 !ui->proxyDefaultBtn->isChecked());
+    bool enableEditing = ui->proxyHTTPBtn->isChecked()
+        || ui->proxySOCKS5Btn->isChecked();
+    ui->proxyAddrBox->setEnabled(enableEditing);
+    ui->proxyAuthBox->setEnabled(enableEditing);
 }
 
-void ProxyPage::proxyChanged(int)
+void ProxyPage::proxyGroupChanged(QAbstractButton *button)
 {
     updateCheckboxStuff();
 }
diff --git a/launcher/ui/pages/global/ProxyPage.h b/launcher/ui/pages/global/ProxyPage.h
index e3677774..279a9029 100644
--- a/launcher/ui/pages/global/ProxyPage.h
+++ b/launcher/ui/pages/global/ProxyPage.h
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -36,6 +37,7 @@
 #pragma once
 
 #include <memory>
+#include <QAbstractButton>
 #include <QDialog>
 
 #include "ui/pages/BasePage.h"
@@ -73,15 +75,14 @@ public:
     bool apply() override;
     void retranslate() override;
 
+private slots:
+    void proxyGroupChanged(QAbstractButton *button);
+
 private:
     void updateCheckboxStuff();
     void applySettings();
     void loadSettings();
 
-private
-slots:
-    void proxyChanged(int);
-
 private:
     Ui::ProxyPage *ui;
 };
diff --git a/launcher/ui/pages/instance/ExternalResourcesPage.cpp b/launcher/ui/pages/instance/ExternalResourcesPage.cpp
index 02eeae3d..d06f412b 100644
--- a/launcher/ui/pages/instance/ExternalResourcesPage.cpp
+++ b/launcher/ui/pages/instance/ExternalResourcesPage.cpp
@@ -32,13 +32,13 @@ class SortProxy : public QSortFilterProxyModel {
         
         const auto& mod = model->at(source_row);
 
-        if (mod.name().contains(filterRegExp()))
+        if (mod.name().contains(filterRegularExpression()))
             return true;
-        if (mod.description().contains(filterRegExp()))
+        if (mod.description().contains(filterRegularExpression()))
             return true;
         
         for (auto& author : mod.authors()) {
-            if (author.contains(filterRegExp())) {
+            if (author.contains(filterRegularExpression())) {
                 return true;
             }
         }
diff --git a/launcher/ui/pages/instance/InstanceSettingsPage.cpp b/launcher/ui/pages/instance/InstanceSettingsPage.cpp
index 1d8cd1d7..fcc110de 100644
--- a/launcher/ui/pages/instance/InstanceSettingsPage.cpp
+++ b/launcher/ui/pages/instance/InstanceSettingsPage.cpp
@@ -2,7 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/instance/LogPage.cpp b/launcher/ui/pages/instance/LogPage.cpp
index 8fefb44c..3d9fb025 100644
--- a/launcher/ui/pages/instance/LogPage.cpp
+++ b/launcher/ui/pages/instance/LogPage.cpp
@@ -63,7 +63,7 @@ public:
         {
             case Qt::FontRole:
                 return m_font;
-            case Qt::TextColorRole:
+            case Qt::ForegroundRole:
             {
                 MessageLevel::Enum level = (MessageLevel::Enum) QIdentityProxyModel::data(index, LogModel::LevelRole).toInt();
                 return m_colors->getFront(level);
diff --git a/launcher/ui/pages/instance/ModFolderPage.h b/launcher/ui/pages/instance/ModFolderPage.h
index 1a9ed7db..19caa732 100644
--- a/launcher/ui/pages/instance/ModFolderPage.h
+++ b/launcher/ui/pages/instance/ModFolderPage.h
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/instance/ScreenshotsPage.cpp b/launcher/ui/pages/instance/ScreenshotsPage.cpp
index 51163e28..c97253e4 100644
--- a/launcher/ui/pages/instance/ScreenshotsPage.cpp
+++ b/launcher/ui/pages/instance/ScreenshotsPage.cpp
@@ -50,6 +50,7 @@
 #include <QClipboard>
 #include <QKeyEvent>
 #include <QMenu>
+#include <QRegularExpression>
 
 #include <Application.h>
 
@@ -154,7 +155,7 @@ public:
         if (role == Qt::DisplayRole || role == Qt::EditRole)
         {
             QVariant result = sourceModel()->data(mapToSource(proxyIndex), role);
-            return result.toString().remove(QRegExp("\\.png$"));
+            return result.toString().remove(QRegularExpression("\\.png$"));
         }
         if (role == Qt::DecorationRole)
         {
@@ -270,7 +271,7 @@ ScreenshotsPage::ScreenshotsPage(QString path, QWidget *parent)
     ui->listView->setViewMode(QListView::IconMode);
     ui->listView->setResizeMode(QListView::Adjust);
     ui->listView->installEventFilter(this);
-    ui->listView->setEditTriggers(0);
+    ui->listView->setEditTriggers(QAbstractItemView::NoEditTriggers);
     ui->listView->setItemDelegate(new CenteredEditingDelegate(this));
     ui->listView->setContextMenuPolicy(Qt::CustomContextMenu);
     connect(ui->listView, &QListView::customContextMenuRequested, this, &ScreenshotsPage::ShowContextMenu);
diff --git a/launcher/ui/pages/instance/ServersPage.cpp b/launcher/ui/pages/instance/ServersPage.cpp
index 3971d422..e5cce96c 100644
--- a/launcher/ui/pages/instance/ServersPage.cpp
+++ b/launcher/ui/pages/instance/ServersPage.cpp
@@ -288,7 +288,11 @@ public:
             return false;
         }
         beginMoveRows(QModelIndex(), row, row, QModelIndex(), row - 1);
+#if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
+        m_servers.swapItemsAt(row-1, row);
+#else
         m_servers.swap(row-1, row);
+#endif
         endMoveRows();
         scheduleSave();
         return true;
@@ -306,7 +310,11 @@ public:
             return false;
         }
         beginMoveRows(QModelIndex(), row, row, QModelIndex(), row + 2);
+#if QT_VERSION >= QT_VERSION_CHECK(5, 13, 0)
+        m_servers.swapItemsAt(row+1, row);
+#else
         m_servers.swap(row+1, row);
+#endif
         endMoveRows();
         scheduleSave();
         return true;
@@ -615,7 +623,7 @@ ServersPage::ServersPage(InstancePtr inst, QWidget* parent)
 
     auto selectionModel = ui->serversView->selectionModel();
     connect(selectionModel, &QItemSelectionModel::currentChanged, this, &ServersPage::currentChanged);
-    connect(m_inst.get(), &MinecraftInstance::runningStatusChanged, this, &ServersPage::on_RunningState_changed);
+    connect(m_inst.get(), &MinecraftInstance::runningStatusChanged, this, &ServersPage::runningStateChanged);
     connect(ui->nameLine, &QLineEdit::textEdited, this, &ServersPage::nameEdited);
     connect(ui->addressLine, &QLineEdit::textEdited, this, &ServersPage::addressEdited);
     connect(ui->resourceComboBox, SIGNAL(currentIndexChanged(int)), this, SLOT(resourceIndexChanged(int)));
@@ -655,7 +663,7 @@ QMenu * ServersPage::createPopupMenu()
     return filteredMenu;
 }
 
-void ServersPage::on_RunningState_changed(bool running)
+void ServersPage::runningStateChanged(bool running)
 {
     if(m_locked == running)
     {
diff --git a/launcher/ui/pages/instance/ServersPage.h b/launcher/ui/pages/instance/ServersPage.h
index 5173712c..37399d49 100644
--- a/launcher/ui/pages/instance/ServersPage.h
+++ b/launcher/ui/pages/instance/ServersPage.h
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -97,7 +98,7 @@ private slots:
     void on_actionMove_Down_triggered();
     void on_actionJoin_triggered();
 
-    void on_RunningState_changed(bool running);
+    void runningStateChanged(bool running);
 
     void nameEdited(const QString & name);
     void addressEdited(const QString & address);
diff --git a/launcher/ui/pages/instance/VersionPage.cpp b/launcher/ui/pages/instance/VersionPage.cpp
index 23e2367b..468ff35c 100644
--- a/launcher/ui/pages/instance/VersionPage.cpp
+++ b/launcher/ui/pages/instance/VersionPage.cpp
@@ -2,7 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/modplatform/ImportPage.cpp b/launcher/ui/pages/modplatform/ImportPage.cpp
index 0b8577b1..30196aad 100644
--- a/launcher/ui/pages/modplatform/ImportPage.cpp
+++ b/launcher/ui/pages/modplatform/ImportPage.cpp
@@ -2,7 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/modplatform/flame/FlameModPage.cpp b/launcher/ui/pages/modplatform/flame/FlameModPage.cpp
index 1c160fd4..10d34218 100644
--- a/launcher/ui/pages/modplatform/flame/FlameModPage.cpp
+++ b/launcher/ui/pages/modplatform/flame/FlameModPage.cpp
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 /*
  *  PolyMC - Minecraft Launcher
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/modplatform/flame/FlameModPage.h b/launcher/ui/pages/modplatform/flame/FlameModPage.h
index 86e1a17b..445d0368 100644
--- a/launcher/ui/pages/modplatform/flame/FlameModPage.h
+++ b/launcher/ui/pages/modplatform/flame/FlameModPage.h
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 /*
  *  PolyMC - Minecraft Launcher
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp b/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp
index c13b1554..2d135e59 100644
--- a/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp
+++ b/launcher/ui/pages/modplatform/legacy_ftb/ListModel.cpp
@@ -168,7 +168,7 @@ QVariant ListModel::data(const QModelIndex &index, int role) const
         ((ListModel *)this)->requestLogo(pack.logo);
         return icon;
     }
-    else if(role == Qt::TextColorRole)
+    else if(role == Qt::ForegroundRole)
     {
         if(pack.broken)
         {
diff --git a/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp b/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp
index 7667d169..6ffbd312 100644
--- a/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp
+++ b/launcher/ui/pages/modplatform/legacy_ftb/Page.cpp
@@ -2,6 +2,7 @@
 /*
  *  PolyMC - Minecraft Launcher
  *  Copyright (c) 2022 Jamie Mansfield <jmansfield@cadixdev.org>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -151,7 +152,7 @@ void Page::openedImpl()
 
         ftbFetchTask->fetch();
         ftbPrivatePacks->load();
-        ftbFetchTask->fetchPrivate(ftbPrivatePacks->getCurrentPackCodes().toList());
+        ftbFetchTask->fetchPrivate(ftbPrivatePacks->getCurrentPackCodes().values());
         initialized = true;
     }
     suggestCurrent();
diff --git a/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.cpp b/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.cpp
index 0b81ea93..5fa00b9b 100644
--- a/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.cpp
+++ b/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.cpp
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 /*
  *  PolyMC - Minecraft Launcher
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.h b/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.h
index c39acaa0..94985f63 100644
--- a/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.h
+++ b/launcher/ui/pages/modplatform/modrinth/ModrinthModPage.h
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 /*
  *  PolyMC - Minecraft Launcher
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/widgets/CustomCommands.cpp b/launcher/ui/widgets/CustomCommands.cpp
index 5a718b54..5ab90395 100644
--- a/launcher/ui/widgets/CustomCommands.cpp
+++ b/launcher/ui/widgets/CustomCommands.cpp
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 /*
  *  PolyMC - Minecraft Launcher
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/widgets/CustomCommands.h b/launcher/ui/widgets/CustomCommands.h
index 4a7a17ef..ed10ba95 100644
--- a/launcher/ui/widgets/CustomCommands.h
+++ b/launcher/ui/widgets/CustomCommands.h
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 /*
  *  PolyMC - Minecraft Launcher
- *  Copyright (c) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
diff --git a/launcher/ui/widgets/LabeledToolButton.cpp b/launcher/ui/widgets/LabeledToolButton.cpp
index ab2d3278..f52e49c9 100644
--- a/launcher/ui/widgets/LabeledToolButton.cpp
+++ b/launcher/ui/widgets/LabeledToolButton.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *          http://www.apache.org/licenses/LICENSE-2.0
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QLabel>
@@ -80,9 +100,7 @@ QSize LabeledToolButton::sizeHint() const
     if (popupMode() == MenuButtonPopup)
         w += style()->pixelMetric(QStyle::PM_MenuButtonIndicator, &opt, this);
     
-    QSize rawSize = style()->sizeFromContents(QStyle::CT_ToolButton, &opt, QSize(w, h), this);
-    QSize sizeHint = rawSize.expandedTo(QApplication::globalStrut());
-    return sizeHint;
+    return style()->sizeFromContents(QStyle::CT_ToolButton, &opt, QSize(w, h), this);
 }
 
 
diff --git a/launcher/ui/widgets/LogView.cpp b/launcher/ui/widgets/LogView.cpp
index 26a2a527..9c46438d 100644
--- a/launcher/ui/widgets/LogView.cpp
+++ b/launcher/ui/widgets/LogView.cpp
@@ -1,3 +1,38 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
+ */
+
 #include "LogView.h"
 #include <QTextBlock>
 #include <QScrollBar>
@@ -102,7 +137,7 @@ void LogView::rowsInserted(const QModelIndex& parent, int first, int last)
         {
             format.setFont(font.value<QFont>());
         }
-        auto fg = m_model->data(idx, Qt::TextColorRole);
+        auto fg = m_model->data(idx, Qt::ForegroundRole);
         if(fg.isValid())
         {
             format.setForeground(fg.value<QColor>());
diff --git a/launcher/ui/widgets/PageContainer.cpp b/launcher/ui/widgets/PageContainer.cpp
index 2af7d731..419ccb66 100644
--- a/launcher/ui/widgets/PageContainer.cpp
+++ b/launcher/ui/widgets/PageContainer.cpp
@@ -66,7 +66,7 @@ public:
 protected:
     bool filterAcceptsRow(int sourceRow, const QModelIndex &sourceParent) const
     {
-        const QString pattern = filterRegExp().pattern();
+        const QString pattern = filterRegularExpression().pattern();
         const auto model = static_cast<PageModel *>(sourceModel());
         const auto page = model->pages().at(sourceRow);
         if (!page->shouldDisplay())
@@ -171,7 +171,7 @@ void PageContainer::createUI()
     headerHLayout->addSpacerItem(new QSpacerItem(rightMargin, 0, QSizePolicy::Fixed, QSizePolicy::Ignored));
     headerHLayout->setContentsMargins(0, 6, 0, 0);
 
-    m_pageStack->setMargin(0);
+    m_pageStack->setContentsMargins(0, 0, 0, 0);
     m_pageStack->addWidget(new QWidget(this));
 
     m_layout = new QGridLayout;
diff --git a/launcher/ui/widgets/VersionListView.cpp b/launcher/ui/widgets/VersionListView.cpp
index aba0b1a1..0e126c65 100644
--- a/launcher/ui/widgets/VersionListView.cpp
+++ b/launcher/ui/widgets/VersionListView.cpp
@@ -1,16 +1,36 @@
-/* Copyright 2013-2021 MultiMC Contributors
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  PolyMC - Minecraft Launcher
+ *  Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
  *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
  *
- *     http://www.apache.org/licenses/LICENSE-2.0
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
  *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ * This file incorporates work covered by the following copyright and
+ * permission notice:
+ *
+ *      Copyright 2013-2021 MultiMC Contributors
+ *
+ *      Licensed under the Apache License, Version 2.0 (the "License");
+ *      you may not use this file except in compliance with the License.
+ *      You may obtain a copy of the License at
+ *
+ *          http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *      Unless required by applicable law or agreed to in writing, software
+ *      distributed under the License is distributed on an "AS IS" BASIS,
+ *      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *      See the License for the specific language governing permissions and
+ *      limitations under the License.
  */
 
 #include <QHeaderView>
@@ -136,7 +156,7 @@ void VersionListView::paintInfoLabel(QPaintEvent *event) const
     auto innerBounds = bounds;
     innerBounds.adjust(10, 10, -10, -10);
 
-    QColor background = QApplication::palette().color(QPalette::Foreground);
+    QColor background = QApplication::palette().color(QPalette::WindowText);
     QColor foreground = QApplication::palette().color(QPalette::Base);
     foreground.setAlpha(190);
     painter.setFont(font);