diff --git a/Caesium.pro b/Caesium.pro
index fcd8791..2613d69 100644
--- a/Caesium.pro
+++ b/Caesium.pro
@@ -4,7 +4,7 @@
 #
 #-------------------------------------------------
 
-QT       += core gui network widgets
+QT       += core gui network widgets concurrent
 
 TARGET = Caesium
 TEMPLATE = app
diff --git a/caesium.cpp b/caesium.cpp
index 9b73d99..8c55396 100644
--- a/caesium.cpp
+++ b/caesium.cpp
@@ -34,8 +34,8 @@
 #include "loadpreview.h"
 #include "imageresize.h"
 
-#include <QtWidgets/QStyleFactory>
-#include <QtWidgets/QScrollBar>
+#include <QStyleFactory>
+#include <QScrollBar>
 #include <QtConcurrent/QtConcurrent>
 #include <QFileDialog>
 #include <QMessageBox>
@@ -48,6 +48,10 @@
 #include <QNetworkReply>
 #include <QNetworkAccessManager>
 #include <QProgressDialog>
+#include <QImageReader>
+#include <QDesktopServices>
+#include <QActionGroup>
+#include <QMovie>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -216,7 +220,9 @@ Caesium::Caesium(QWidget *parent) :
 
     QDir::setCurrent(QFileInfo(QCoreApplication::arguments().at(0)).absolutePath());
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     settings.setIniCodec("UTF-8");
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 
     QApplication::setStyle(QStyleFactory::create(settings.value("Preferences/style").value<QString>()));
     QApplication::setPalette(QApplication::style()->standardPalette());
@@ -708,7 +714,9 @@ void Caesium::on_setQualityButton_clicked()
 
 void Caesium::on_actionPreview_triggered()
 {
-    QtConcurrent::run(this, &Caesium::runPreview);
+    [[maybe_unused]] QFuture<void> future = QtConcurrent::run([this](){
+        this->runPreview();
+    });
 }
 
 void Caesium::on_previewButton_clicked()
@@ -1006,7 +1014,7 @@ void Caesium::on_cancelButton_clicked()
 
 void Caesium::on_suffixLineEdit_textChanged(QString text)
 {
-    QRegExp rx("[\\/|:*<>]");
+    QRegularExpression rx("[\\/|:*<>]");
     if (text.contains(rx))
     {
         ui->suffixErrorLabel->setVisible(true);
@@ -1287,7 +1295,9 @@ void Caesium::on_actionSave_Profile_triggered()
     if (fileName != "")
     {
         QSettings profile(fileName, QSettings::IniFormat);
-        profile.setIniCodec("UTF-8");
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+        settings.setIniCodec("UTF-8");
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
         profile.setValue("Profile/quality", ui->qualitySlider->value());
         profile.setValue("Profile/same_quality", ui->sameLevelCheckBox->isChecked());
         profile.setValue("Profile/format", ui->formatComboBox->currentIndex());
@@ -1321,7 +1331,9 @@ void Caesium::profileLoadEngine(QString fileName)
     if (fileName != "")
     {
         QSettings profile(fileName, QSettings::IniFormat);
-        profile.setIniCodec("UTF-8");
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+        settings.setIniCodec("UTF-8");
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
         ui->qualitySlider->setValue(profile.value("Profile/quality").value<int>());
         ui->sameLevelCheckBox->setChecked(profile.value("Profile/same_quality").value<bool>());
         ui->formatComboBox->setCurrentIndex(profile.value("Profile/format").value<int>());
diff --git a/compressionthread.cpp b/compressionthread.cpp
index a86fd13..91f5915 100644
--- a/compressionthread.cpp
+++ b/compressionthread.cpp
@@ -33,6 +33,8 @@
 #include <QMessageBox>
 #include <QDebug>
 #include <QProgressDialog>
+#include <QFileInfo>
+#include <QDir>
 
 #include <windows.h>
 #include <afxres.h>
@@ -100,7 +102,9 @@ CompressionThread::CompressionThread(QStringList list, QString orig_dir, QString
     t_resize = resize;
     t_structure = structure;
     t_orig_dir = orig_dir;
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     settings.setIniCodec("UTF-8");
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 }
 
 QString t_getRatio(int origSize, int newSize)
diff --git a/compressionthread.h b/compressionthread.h
index 60cc0bd..b45a057 100644
--- a/compressionthread.h
+++ b/compressionthread.h
@@ -1,7 +1,7 @@
 #ifndef COMPRESSIONTHREAD_H
 #define COMPRESSIONTHREAD_H
 
-#include <QtGui>
+#include <QThread>
 
 class CompressionThread : public QThread
 {
diff --git a/global.cpp b/global.cpp
index f7f2487..6a27c61 100644
--- a/global.cpp
+++ b/global.cpp
@@ -24,10 +24,10 @@
 
 #include <QString>
 #include <QDir>
-#include <QDesktopServices>
+#include <QStandardPaths>
 #include "global.h"
 
-QSettings settings(QStandardPaths::standardLocations(QStandardPaths::DataLocation).at(0) + "/Caesium/settings.ini", QSettings::IniFormat);
+QSettings settings(QStandardPaths::standardLocations(QStandardPaths::AppLocalDataLocation).at(0) + "/Caesium/settings.ini", QSettings::IniFormat);
 QString out_folder = "";
 bool same_folder_flag = false;
 const int version_build = 170;
diff --git a/main.cpp b/main.cpp
index ddfad18..c387685 100644
--- a/main.cpp
+++ b/main.cpp
@@ -24,13 +24,16 @@
 #
 # ******************************************************************************/
 
-#include <QtWidgets/QApplication>
-#include <QtWidgets/QSplashScreen>
+#include <QApplication>
+#include <QSplashScreen>
 #include <QString>
 #include "caesium.h"
 #include "global.h"
 #include <QDebug>
 #include <QTextStream>
+#include <QDir>
+#include <QTranslator>
+#include <QBitmap>
 
 // QM_FILE_INSTALL_DIR should be defined from the CMakeLists file.
 #ifndef QM_FILE_INSTALL_DIR
@@ -42,7 +45,9 @@ int main(int argc, char *argv[])
     QApplication a(argc, argv);
     Q_INIT_RESOURCE(icons);
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     settings.setIniCodec("UTF-8");
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
 
     a.addLibraryPath(a.applicationDirPath() + "/lib/");
 
diff --git a/preferences.cpp b/preferences.cpp
index 21114d1..212b476 100644
--- a/preferences.cpp
+++ b/preferences.cpp
@@ -44,7 +44,9 @@ Preferences::Preferences(QWidget *parent) :
     ui(new Ui::Preferences)
 {
     ui->setupUi(this);
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     settings.setIniCodec("UTF-8");
+#endif // QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     loadSettings();
     loadLanguages();
     Preferences::on_pngLevelSlider_valueChanged(settings.value("Preferences/pnglevel").value<int>());
diff --git a/qdroptreewidget.cpp b/qdroptreewidget.cpp
index aee445a..559edfa 100644
--- a/qdroptreewidget.cpp
+++ b/qdroptreewidget.cpp
@@ -26,9 +26,13 @@
 #include "global.h"
 #include "caesium.h"
 
-#include <QtWidgets/QAction>
-#include <QtWidgets/QMenu>
+#include <QAction>
+#include <QMenu>
 #include <QStringList>
+#include <QImageReader>
+#include <QDirIterator>
+#include <QDesktopServices>
+#include <QMimeData>
 
 QDropTreeWidget::QDropTreeWidget(QWidget *parent)
     : QTreeWidget(parent)
diff --git a/startupupdater.h b/startupupdater.h
index 7af6377..b57d827 100644
--- a/startupupdater.h
+++ b/startupupdater.h
@@ -1,7 +1,7 @@
 #ifndef STARTUPUPDATER_H
 #define STARTUPUPDATER_H
 
-#include <QtGui>
+#include <QThread>
 #include <QNetworkReply>
 #include <QNetworkAccessManager>
 
diff --git a/updater.cpp b/updater.cpp
index 11a0de1..2ece550 100644
--- a/updater.cpp
+++ b/updater.cpp
@@ -30,6 +30,7 @@
 #include <QtCore>
 #include <QtGui>
 #include <QtNetwork>
+#include <QMessageBox>
 
 #include <stdlib.h>
 #include <stdio.h>
diff --git a/updater.h b/updater.h
index 3e2427e..86bad1e 100644
--- a/updater.h
+++ b/updater.h
@@ -1,12 +1,11 @@
 #ifndef UPDATER_H
 #define UPDATER_H
 
-#include <QtWidgets/QDialog>
-#include <QtWidgets/QMessageBox>
+#include <QDialog>
 #include <QCloseEvent>
 #include <QFile>
 #include <QTimer>
-#include <QtNetwork>
+#include <QNetworkReply>
 
 namespace Ui {
     class Updater;