diff --git a/.gitignore b/.gitignore
index d2652689e..6a66aa0fd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -16,3 +16,6 @@
 # binaries
 /src/smplayer
 /webserver/simple_web_server
+webserver/simple_web_server.exe
+version
+src/smplayer.pro.user
diff --git a/src/actionseditor.cpp b/src/actionseditor.cpp
index 8d21fa58c..abbba28a7 100644
--- a/src/actionseditor.cpp
+++ b/src/actionseditor.cpp
@@ -37,6 +37,9 @@
 #include <QMessageBox>
 #include <QFileInfo>
 #include <QRegExp>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegularExpression>
+#endif
 #include <QApplication>
 #include <QAction>
 #include <QDebug>
@@ -539,7 +542,9 @@ bool ActionsEditor::saveActionsTable(const QString & filename) {
 	QFile f( filename );
 	if ( f.open( QIODevice::WriteOnly ) ) {
 		QTextStream stream( &f );
+#if QT_VERSION_MAJOR < 6
 		stream.setCodec("UTF-8");
+#endif
 
 		for (int row = 0; row < table->rowCount(); row++) {
 			stream << table->item(row, COL_NAME)->text() << "\t" 
@@ -580,7 +585,9 @@ bool ActionsEditor::loadActionsTable(const QString & filename) {
 		#endif
 
 		QTextStream stream( &f );
-		stream.setCodec("UTF-8");
+#if QT_VERSION_MAJOR < 6
+        stream.setCodec("UTF-8");
+#endif
 
 		QString line;
 		while ( !stream.atEnd() ) {
@@ -588,7 +595,11 @@ bool ActionsEditor::loadActionsTable(const QString & filename) {
 			qDebug() << "ActionsEditor::loadActions: line:" << line;
 			QString name;
 			QString accelText;
-			int pos = line.indexOf(QRegExp("\\t|\\s"));
+#if QT_VERSION_MAJOR < 6
+            int pos = line.indexOf(QRegExp("\\t|\\s"));
+#else
+            int pos = line.indexOf(QRegularExpression("\\t|\\s"));
+#endif
 			//qDebug() << "ActionsEditor::loadActions: pos:" << pos;
 			if (pos == -1) {
 				name = line;
diff --git a/src/basegui.cpp b/src/basegui.cpp
index e709a6d27..793bbc3b6 100644
--- a/src/basegui.cpp
+++ b/src/basegui.cpp
@@ -39,7 +39,11 @@
 #include <QInputDialog>
 #include <QClipboard>
 #include <QMimeData>
+#if QT_VERSION_MAJOR < 6
 #include <QDesktopWidget>
+#else
+#include <QOperatingSystemVersion>
+#endif
 
 #include <QtCore/qmath.h>
 
@@ -3826,7 +3830,11 @@ void BaseGui::updateRecents() {
 			//if (fi.exists()) filename = fi.fileName(); // Can be slow
 
 			// Let's see if it looks like a file (no dvd://1 or something)
-			if (fullname.indexOf(QRegExp("^.*://.*")) == -1) filename = fi.fileName();
+#if QT_VERSION_MAJOR < 6
+            if (fullname.indexOf(QRegExp("^.*://.*")) == -1) filename = fi.fileName();
+#else
+            if (fullname.indexOf(QRegularExpression("^.*://.*")) == -1) filename = fi.fileName();
+#endif
 
 			if (filename.size() > 85) {
 				filename = filename.left(80) + "...";
@@ -4831,9 +4839,13 @@ void BaseGui::toggleFullscreen(bool b) {
 
 		aboutToEnterFullscreen();
 
-		#ifdef Q_OS_WIN
+        #ifdef Q_OS_WIN
 		// Hack to avoid the windows taskbar to be visible on Windows XP
-		if (QSysInfo::WindowsVersion < QSysInfo::WV_VISTA) {
+#if QT_VERSION_MAJOR < 6
+        if (QSysInfo::WindowsVersion < QSysInfo::WV_VISTA) {
+#else
+        if (QOperatingSystemVersion::current() < QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 }) {
+#endif
 			if (!pref->pause_when_hidden) hide();
 		}
 		#endif
@@ -5541,7 +5553,11 @@ void BaseGui::resizeMainWindow(int w, int h) {
 	int diff_height = this->height() - panel->height();
 
 #if 1
+#if QT_VERSION_MAJOR < 6
 	QRect desktop_rect = QApplication::desktop()->availableGeometry(this);
+#else
+    QRect desktop_rect = QGuiApplication::primaryScreen()->availableGeometry();
+#endif
 	QSize desktop_size = QSize(desktop_rect.width(), desktop_rect.height());
 
 	if (w + diff_width > desktop_size.width() || h + diff_height > desktop_size.height()) {
@@ -5609,8 +5625,12 @@ void BaseGui::resizeMainWindow(int w, int h) {
 	// Check if a part of the window is outside of the desktop
 	// and center the window in that case
 	if ((pref->center_window_if_outside) && (!core->mdat.novideo)) {
-		QRect screen_rect = QApplication::desktop()->availableGeometry(this);
-		QPoint right_bottom = QPoint(this->pos().x() + this->width(), this->pos().y() + this->height());
+#if QT_VERSION_MAJOR < 6
+        QRect screen_rect = QApplication::desktop()->availableGeometry(this);
+#else
+        QRect screen_rect = QGuiApplication::primaryScreen()->availableGeometry();
+#endif
+        QPoint right_bottom = QPoint(this->pos().x() + this->width(), this->pos().y() + this->height());
 		qDebug("BaseGui::resizeWindow: right bottom point: %d, %d", right_bottom.x(), right_bottom.y());;
 		if (!screen_rect.contains(right_bottom) || !screen_rect.contains(this->pos())) {
 			qDebug("BaseGui::resizeWindow: the window is outside of the desktop, it will be moved");
@@ -5655,8 +5675,12 @@ void BaseGui::hidePanel() {
 void BaseGui::centerWindow() {
 	qDebug("BaseGui::centerWindow");
 	if (pref->center_window && !pref->fullscreen && isVisible()) {
-		QRect r = QApplication::desktop()->screenGeometry(this);
-		// r.setX(500); r.setY(150); // Test
+#if QT_VERSION_MAJOR < 6
+        QRect r = QApplication::desktop()->availableGeometry(this);
+#else
+        QRect r = QGuiApplication::primaryScreen()->availableGeometry();
+#endif
+        // r.setX(500); r.setY(150); // Test
 		qDebug() << "BaseGui::centerWindow: desktop rect:" << r;
 		int x = r.x() + ((r.width() - width()) / 2);
 		int y = r.y() + ((r.height() - height()) / 2);
@@ -5822,8 +5846,13 @@ QString BaseGui::loadQss(QString filename) {
 		path = current.relativeFilePath(td);
 	}
 #endif
+#if QT_VERSION_MAJOR < 6
 	stylesheet.replace(QRegExp("url\\s*\\(\\s*([^\\);]+)\\s*\\)", Qt::CaseSensitive, QRegExp::RegExp2),
 						QString("url(%1\\1)").arg(path + "/"));
+#else
+    stylesheet.replace(QRegularExpression("url\\s*\\(\\s*([^\\);]+)\\s*\\)", QRegularExpression::CaseInsensitiveOption),
+                       QString("url(%1\\1)").arg(path + "/"));
+#endif
 	//qDebug("BaseGui::loadQss: styleSheet: %s", stylesheet.toUtf8().constData());
 	return stylesheet;
 }
@@ -6408,18 +6437,30 @@ bool BaseGui::winEvent ( MSG * m, long * result ) {
 		QString text = QString::fromWCharArray((TCHAR*)m->lParam);
 		qDebug() << "BaseGui::winEvent: WM_SETTINGCHANGE:" << text;
 
-		#if ((QT_VERSION >= 0x040807 && QT_VERSION < 0x050000) || (QT_VERSION >= 0x050500))
+        #if ((QT_VERSION >= 0x040807 && QT_VERSION < 0x050000) || (QT_VERSION >= 0x050500))
+#if QT_VERSION_MAJOR < 6
 		if (QSysInfo::windowsVersion() >= QSysInfo::WV_WINDOWS10) {
+#else
+        if (QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows10) {
+#endif
 			// Windows 10 check
 			if (text == "UserInteractionMode") {
 				QTimer::singleShot(1000, this, SLOT(checkSystemTabletMode()));
 			}
 		}
 		else 
-		if (QSysInfo::windowsVersion() == QSysInfo::WV_WINDOWS8_1) {
-			if (text == "ConvertibleSlateMode") checkSystemTabletMode();
+#if QT_VERSION_MAJOR < 6
+        if (QSysInfo::windowsVersion() == QSysInfo::WV_WINDOWS8_1) {
+#else
+        if (QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows8_1 && QOperatingSystemVersion::current() <= QOperatingSystemVersion::Windows8_1) {
+#endif
+            if (text == "ConvertibleSlateMode") checkSystemTabletMode();
 		}
-		#endif
+        #else
+        if (text == "UserInteractionMode") {
+            QTimer::singleShot(1000, this, SLOT(checkSystemTabletMode()));
+        }
+        #endif
 		
 		*result = 0;
 		return true;
@@ -6468,7 +6509,11 @@ bool BaseGui::nativeEvent(const QByteArray &eventType, void * message, long * re
 
 void BaseGui::checkSystemTabletMode() {
 	#if ((QT_VERSION >= 0x040807 && QT_VERSION < 0x050000) || (QT_VERSION >= 0x050500))
-	if (QSysInfo::windowsVersion() >= QSysInfo::WV_WINDOWS10) {
+    #if QT_VERSION_MAJOR < 6
+    if (QSysInfo::windowsVersion() >= QSysInfo::WV_WINDOWS10) {
+    #else
+    if (QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows10) {
+    #endif
 		// Windows 10 code (don't know if this works on Windows 8)
 		QSettings set("HKEY_CURRENT_USER\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\ImmersiveShell", QSettings::NativeFormat);
 		QVariant v = set.value("TabletMode");
@@ -6479,8 +6524,12 @@ void BaseGui::checkSystemTabletMode() {
 		}
 	}
 	else
-	if (QSysInfo::windowsVersion() == QSysInfo::WV_WINDOWS8_1 || 
+#if QT_VERSION_MAJOR < 6
+    if (QSysInfo::windowsVersion() == QSysInfo::WV_WINDOWS8_1 ||
         QSysInfo::windowsVersion() == QSysInfo::WV_WINDOWS8)
+#else
+    if (QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows8 && QOperatingSystemVersion::current() <= QOperatingSystemVersion::Windows8_1)
+#endif
 	{
 		bool slate_mode = (GetSystemMetrics(SM_CONVERTIBLESLATEMODE) == 0);
 		qDebug() << "BaseGui::checkSystemTabletMode: slate_mode:" << slate_mode;
diff --git a/src/baseguiplus.cpp b/src/baseguiplus.cpp
index 81134b56c..31c93cbd2 100644
--- a/src/baseguiplus.cpp
+++ b/src/baseguiplus.cpp
@@ -35,7 +35,9 @@
 #include <QMenu>
 #include <QCloseEvent>
 #include <QApplication>
+#if QT_VERSION_MAJOR < 6
 #include <QDesktopWidget>
+#endif
 #include <QTime>
 
 #ifdef PLAYLIST_DOCKABLE
@@ -624,8 +626,16 @@ void BaseGuiPlus::aboutToEnterFullscreen() {
 	if (!playlist->isWindow() && playlistdock) {
 		playlistdock->setAllowedAreas(Qt::NoDockWidgetArea);
 
+#if QT_VERSION_MAJOR < 6
 		int playlist_screen = QApplication::desktop()->screenNumber(playlistdock);
 		int mainwindow_screen = QApplication::desktop()->screenNumber(this);
+#else
+        const QList<QScreen *> screens = QGuiApplication::screens();
+        QScreen *primaryScreen = QGuiApplication::primaryScreen();
+        QScreen *pldockScreen = playlistdock->windowHandle()->screen();
+        int playlist_screen = screens.indexOf(pldockScreen);
+        int mainwindow_screen = screens.indexOf(primaryScreen);
+#endif
 		qDebug("BaseGuiPlus::aboutToEnterFullscreen: mainwindow screen: %d, playlist screen: %d", mainwindow_screen, playlist_screen);
 
 		fullscreen_playlist_was_visible = playlistdock->isVisible();
diff --git a/src/colorutils.cpp b/src/colorutils.cpp
index 1000f97f6..a8ea962f7 100644
--- a/src/colorutils.cpp
+++ b/src/colorutils.cpp
@@ -18,6 +18,9 @@
 
 #include "colorutils.h"
 #include <QWidget>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#endif
 #include <QDebug>
 #include "qtcompat.h"
 
diff --git a/src/defaultgui.cpp b/src/defaultgui.cpp
index f27d4b10f..a223b23ee 100644
--- a/src/defaultgui.cpp
+++ b/src/defaultgui.cpp
@@ -47,6 +47,9 @@
 #include <QMenuBar>
 #include <QMovie>
 #include <QtCore/qmath.h>
+#if QT_VERSION_MAJOR >= 6
+#include <QActionGroup>
+#endif
 
 #define TOOLBAR_VERSION "2"
 #define CONTROLWIDGET_VERSION "1"
diff --git a/src/deviceinfo.cpp b/src/deviceinfo.cpp
index f4acefbca..399e0d8be 100644
--- a/src/deviceinfo.cpp
+++ b/src/deviceinfo.cpp
@@ -21,6 +21,9 @@
 #include <QProcess>
 #include <QFile>
 #include <QSettings>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#endif
 #include <QDebug>
 
 #ifdef Q_OS_WIN
diff --git a/src/favorites.cpp b/src/favorites.cpp
index c06e97ac9..223ac0697 100644
--- a/src/favorites.cpp
+++ b/src/favorites.cpp
@@ -25,6 +25,9 @@
 #include <QTextStream>
 #include <QInputDialog>
 #include <QFileInfo>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#endif
 
 //#define FIRST_MENU_ENTRY 4
 #define FIRST_MENU_ENTRY 3
@@ -270,7 +273,11 @@ void Favorites::save() {
 	QFile f( _filename );
     if ( f.open( QIODevice::WriteOnly ) ) {
         QTextStream stream( &f );
+#if QT_VERSION_MAJOR < 6
 		stream.setCodec("UTF-8");
+#else
+        stream.setEncoding(QStringConverter::Utf8);
+#endif
 
 		stream << "#EXTM3U" << "\n";
 		for (int n = 0; n < f_list.count(); n++) {
@@ -299,7 +306,11 @@ void Favorites::load() {
 		Favorite fav;
 
 		QTextStream stream( &f );
-		stream.setCodec("UTF-8");
+#if QT_VERSION_MAJOR < 6
+        stream.setCodec("UTF-8");
+#else
+        stream.setEncoding(QStringConverter::Utf8);
+#endif
 
 		QString line;
 		while ( !stream.atEnd() ) {
diff --git a/src/findsubtitles/findsubtitleswindow.cpp b/src/findsubtitles/findsubtitleswindow.cpp
index 40ae27ff5..b9731ee52 100644
--- a/src/findsubtitles/findsubtitleswindow.cpp
+++ b/src/findsubtitles/findsubtitleswindow.cpp
@@ -359,7 +359,11 @@ void FindSubtitlesWindow::currentItemChanged(const QModelIndex & current, const
 }
 
 void FindSubtitlesWindow::applyFilter(const QString & filter) {
+#if QT_VERSION_MAJOR < 6
 	proxy_model->setFilterRegExp(filter);
+#else
+    proxy_model->setFilterRegularExpression(filter);
+#endif
 }
 
 void FindSubtitlesWindow::applyCurrentFilter() {
diff --git a/src/globalshortcuts/globalshortcuts.h b/src/globalshortcuts/globalshortcuts.h
index ee4e9ffb4..906b5b5c6 100644
--- a/src/globalshortcuts/globalshortcuts.h
+++ b/src/globalshortcuts/globalshortcuts.h
@@ -42,7 +42,12 @@ class GlobalShortcuts : public QObject, public QAbstractNativeEventFilter
 	void setGrabbedKeys(MediaKeys keys);
 	MediaKeys grabbedKeys() { return grabbed_keys; };
 
-	virtual bool nativeEventFilter(const QByteArray & eventType, void * message, long * result);
+#if QT_VERSION_MAJOR < 6
+    virtual bool nativeEventFilter(const QByteArray & eventType, void * message, long * result);
+#else
+    virtual bool nativeEventFilter(const QByteArray & eventType, void * message, qintptr * result);
+#endif
+
 
 public slots:
 	void setEnabled(bool);
diff --git a/src/globalshortcuts/globalshortcuts_win.cpp b/src/globalshortcuts/globalshortcuts_win.cpp
index 08e0219cf..39d71f847 100644
--- a/src/globalshortcuts/globalshortcuts_win.cpp
+++ b/src/globalshortcuts/globalshortcuts_win.cpp
@@ -17,9 +17,17 @@
 */
 
 #include <windows.h>
+#include <QDebug>
+#if QT_VERSION_MAJOR >= 6
+#include "globalshortcuts.h"
+#endif
 
+#if QT_VERSION_MAJOR < 6
 bool GlobalShortcuts::nativeEventFilter(const QByteArray & /*eventType*/, void * message, long * /*result*/) {
-	//qDebug() << "GlobalShortcuts::nativeEventFilter";
+#else
+bool GlobalShortcuts::nativeEventFilter(const QByteArray & /*eventType*/, void * message, qintptr * /*result*/) {
+#endif
+    //qDebug() << "GlobalShortcuts::nativeEventFilter";
 
 	if (!isEnabled()) return false;
 
diff --git a/src/helper.cpp b/src/helper.cpp
index 944f29152..f8463a61e 100644
--- a/src/helper.cpp
+++ b/src/helper.cpp
@@ -24,6 +24,10 @@
 #include <QDir>
 #include <QTextCodec>
 #include <QWidget>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#include <QRegularExpression>
+#endif
 #include <QDebug>
 #include "config.h"
 #include "extensions.h"
@@ -253,7 +257,11 @@ QStringList Helper::searchForConsecutiveFiles(const QString & initial_file) {
 		digits = rx.cap(1).length();
 		current_number = rx.cap(1).toInt() + 1;
 		next_name = basename.left(pos) + QString("%1").arg(current_number, digits, 10, QLatin1Char('0'));
-		next_name.replace(QRegExp("([\\[\\]?*])"), "[\\1]");
+#if QT_VERSION_MAJOR < 6
+        next_name.replace(QRegExp("([\\[\\]?*])"), "[\\1]");
+#else
+        next_name.replace(QRegularExpression("([\\[\\]?*])"), "[\\1]");
+#endif
 		next_name += "*." + extension;
 		qDebug("Helper::searchForConsecutiveFiles: next name = %s",next_name.toUtf8().constData());
 		matching_files = dir.entryList((QStringList)next_name);
@@ -277,7 +285,11 @@ QStringList Helper::searchForConsecutiveFiles(const QString & initial_file) {
 			files_to_add << filename;
 			current_number++;
 			next_name = basename.left(pos) + QString("%1").arg(current_number, digits, 10, QLatin1Char('0'));
-			next_name.replace(QRegExp("([\\[\\]?*])"), "[\\1]");
+#if QT_VERSION_MAJOR < 6
+            next_name.replace(QRegExp("([\\[\\]?*])"), "[\\1]");
+#else
+            next_name.replace(QRegularExpression("([\\[\\]?*])"), "[\\1]");
+#endif
 			next_name += "*." + extension;
 			matching_files = dir.entryList((QStringList)next_name);
 			qDebug("Helper::searchForConsecutiveFiles: looking for '%s'", next_name.toUtf8().constData());
diff --git a/src/myapplication.cpp b/src/myapplication.cpp
index f8564343a..64debc5a0 100644
--- a/src/myapplication.cpp
+++ b/src/myapplication.cpp
@@ -53,7 +53,7 @@ MyApplication::MyApplication (const QString & /*appId*/, int & argc, char ** arg
 	: QApplication(argc, argv)
 #endif
 {
-#if QT_VERSION >= 0x050600
+#if QT_VERSION >= 0x050600 && QT_VERSION_MAJOR < 6
 	setFallbackSessionManagementEnabled(false);
 #endif
 #if QT_VERSION >= 0x050000
diff --git a/src/paths.cpp b/src/paths.cpp
index a38f8b1a6..cbb80ba63 100644
--- a/src/paths.cpp
+++ b/src/paths.cpp
@@ -20,7 +20,9 @@
 #include <QLibraryInfo>
 #include <QLocale>
 #include <QFile>
-#include <QRegExp>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegularExpression>
+#endif
 #include <QDir>
 
 #ifndef Q_OS_WIN
@@ -123,8 +125,13 @@ QString Paths::doc(QString file, QString locale, bool english_fallback) {
 	qDebug("Helper:doc: checking '%s'", f.toUtf8().data());
 	if (QFile::exists(f)) return f;
 
-	if (locale.indexOf(QRegExp("_[A-Z]+")) != -1) {
-		locale.replace(QRegExp("_[A-Z]+"), "");
+#if QT_VERSION_MAJOR < 6
+    if (locale.indexOf(QRegExp("_[A-Z]+")) != -1) {
+        locale.replace(QRegExp("_[A-Z]+"), "");
+#else
+    if (locale.indexOf(QRegularExpression("_[A-Z]+")) != -1) {
+        locale.replace(QRegularExpression("_[A-Z]+"), "");
+#endif
 		f = docPath() + "/" + locale + "/" + file;
 		qDebug("Helper:doc: checking '%s'", f.toUtf8().data());
 		if (QFile::exists(f)) return f;
diff --git a/src/playlist.cpp b/src/playlist.cpp
index cfa10a4de..ec07a40fc 100644
--- a/src/playlist.cpp
+++ b/src/playlist.cpp
@@ -46,6 +46,11 @@
 #include <QDomDocument>
 #include <QDesktopServices>
 #include <QClipboard>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#include <QRegularExpression>
+#include <QStringConverter>
+#endif
 #include <QDebug>
 
 #if QT_VERSION >= 0x050000
@@ -931,7 +936,11 @@ void Playlist::addItem(QString filename, QString name, double duration, QStringL
 		if (name.isEmpty()) {
 			QFileInfo fi(filename);
 			// Let's see if it looks like a file (no dvd://1 or something)
-			if (filename.indexOf(QRegExp("^.*://.*")) == -1) {
+#if QT_VERSION_MAJOR < 6
+            if (filename.indexOf(QRegExp("^.*://.*")) == -1) {
+#else
+            if (filename.indexOf(QRegularExpression("^.*://.*")) == -1) {
+#endif
 				// Local file
 				name = fi.fileName();
 			} else {
@@ -1020,9 +1029,21 @@ void Playlist::load_m3u(QString file, M3UFormat format) {
 		QTextStream stream( &f );
 
 		if (utf8)
-			stream.setCodec("UTF-8");
+#if QT_VERSION_MAJOR < 6
+            stream.setCodec("UTF-8");
+#else
+            stream.setEncoding(QStringConverter::Utf8);
+#endif
 		else
-			stream.setCodec(QTextCodec::codecForLocale());
+#if QT_VERSION_MAJOR < 6
+            stream.setCodec(QTextCodec::codecForLocale());
+#else
+        {
+            std::optional<QStringEncoder::Encoding> encodingOpt = QStringConverter::encodingForName(QTextCodec::codecForLocale()->name());
+            QStringEncoder::Encoding encoding = encodingOpt == std::nullopt ? QStringConverter::Utf8 : encodingOpt.value();
+            stream.setEncoding(encoding);
+        }
+#endif
 
 		QString line;
 		while ( !stream.atEnd() ) {
@@ -1174,9 +1195,15 @@ void Playlist::loadXSPF(const QString & filename) {
 	}
 
 	QDomDocument dom_document;
-	bool ok = dom_document.setContent(f.readAll());
-	qDebug() << "Playlist::loadXSPF: success:" << ok;
-	if (!ok) return;
+#if QT_VERSION_MAJOR < 6
+    bool ok = dom_document.setContent(f.readAll());
+    qDebug() << "Playlist::loadXSPF: success:" << ok;
+    if (!ok) return;
+#else
+    auto ok = dom_document.setContent(f.readAll());
+    qDebug() << "Playlist::loadXSPF: success:" << ok.errorMessage;
+    if (!ok) return;
+#endif
 
 	QDomNode root = dom_document.documentElement();
 	qDebug() << "Playlist::loadXSPF: tagname:" << root.toElement().tagName();
@@ -1247,9 +1274,21 @@ bool Playlist::save_m3u(QString file) {
 		QTextStream stream( &f );
 
 		if (utf8)
-			stream.setCodec("UTF-8");
-		else
-			stream.setCodec(QTextCodec::codecForLocale());
+#if QT_VERSION_MAJOR < 6
+            stream.setCodec("UTF-8");
+#else
+            stream.setEncoding(QStringConverter::Utf8);
+#endif
+        else
+#if QT_VERSION_MAJOR < 6
+            stream.setCodec(QTextCodec::codecForLocale());
+#else
+        {
+            std::optional<QStringEncoder::Encoding> encodingOpt = QStringConverter::encodingForName(QTextCodec::codecForLocale()->name());
+            QStringEncoder::Encoding encoding = encodingOpt == std::nullopt ? QStringConverter::Utf8 : encodingOpt.value();
+            stream.setEncoding(encoding);
+        }
+#endif
 
 		QString filename;
 		QString name;
@@ -1351,7 +1390,11 @@ bool Playlist::saveXSPF(const QString & filename) {
 	QFile f(filename);
 	if (f.open( QIODevice::WriteOnly)) {
 		QTextStream stream(&f);
+#if QT_VERSION_MAJOR < 6
 		stream.setCodec("UTF-8");
+#else
+        stream.setEncoding(QStringConverter::Utf8);
+#endif
 
 		stream << "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n";
 		stream << "<playlist version=\"1\" xmlns=\"http://xspf.org/ns/0/\">\n";
diff --git a/src/prefassociations.cpp b/src/prefassociations.cpp
index 0f238ee9a..433cc29b1 100644
--- a/src/prefassociations.cpp
+++ b/src/prefassociations.cpp
@@ -27,6 +27,9 @@
 #include <QSettings>
 #include <QApplication>
 #include <QMessageBox>
+#if QT_VERSION_MAJOR >= 6
+#include <QOperatingSystemVersion>
+#endif
 #include "winfileassoc.h"
 #include "extensions.h"
 
@@ -48,10 +51,14 @@ PrefAssociations::PrefAssociations(QWidget * parent, Qt::WindowFlags f)
 
 	connect(selectAll, SIGNAL(clicked(bool)), this, SLOT(selectAllClicked(bool)));
 	connect(selectNone, SIGNAL(clicked(bool)), this, SLOT(selectNoneClicked(bool)));
-	connect(listWidget, SIGNAL(itemClicked(QListWidgetItem*)), this, SLOT(listItemClicked(QListWidgetItem*))); 
-	connect(listWidget, SIGNAL(itemPressed(QListWidgetItem*)), this, SLOT(listItemPressed(QListWidgetItem*))); 
+    connect(listWidget, SIGNAL(itemClicked(QListWidgetItem*)), this, SLOT(listItemClicked(QListWidgetItem*)));
+    connect(listWidget, SIGNAL(itemPressed(QListWidgetItem*)), this, SLOT(listItemPressed(QListWidgetItem*)));
 
+#if QT_VERSION_MAJOR < 6
 	if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA)
+#else
+    if (QOperatingSystemVersion::current() >= QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 })
+#endif
 	{
 		//Hide Select None - One cannot restore an association in Vista. Go figure.
 		selectNone->hide(); 
@@ -148,7 +155,11 @@ void PrefAssociations::refreshList()
 				pItem->setCheckState(Qt::Checked);
 				//Don't allow de-selection in windows VISTA if extension is registered.
 				//VISTA doesn't seem to support extension 'restoration' in the API.
-				if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA) {
+#if QT_VERSION_MAJOR < 6
+                if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA) {
+#else
+                if (QOperatingSystemVersion::current() >= QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 }) {
+#endif
 					pItem->setFlags(QFlag(0));
 				}
 			}
diff --git a/src/preferences.cpp b/src/preferences.cpp
index 40b7452e0..1265f9e31 100644
--- a/src/preferences.cpp
+++ b/src/preferences.cpp
@@ -40,6 +40,9 @@
 #if QT_VERSION >= 0x040400
 #include <QDesktopServices>
 #endif
+#if QT_VERSION_MAJOR >= 6
+#include <QOperatingSystemVersion>
+#endif
 
 #ifdef YOUTUBE_SUPPORT
 #include "retrieveyoutubeurl.h"
@@ -84,10 +87,14 @@ void Preferences::reset() {
 #endif
 
 #if defined(Q_OS_WIN) || defined(Q_OS_OS2)
-	mplayer_bin= "mpv/mpv.exe";
-	if (QSysInfo::WindowsVersion < QSysInfo::WV_WINDOWS7) {
+    mplayer_bin= "mpv/mpv.exe";
+#if QT_VERSION_MAJOR < 6
+    if (QSysInfo::WindowsVersion < QSysInfo::WV_WINDOWS7) {
+#else
+    if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows7) {
+#endif
 		mplayer_bin= "mplayer/mplayer.exe";
-	}
+    }
 #else
 	mplayer_bin = "mpv";
 #endif
@@ -1911,9 +1918,13 @@ void Preferences::load() {
 		}
 		if (config_version <= 5) {
 			#ifdef Q_OS_WIN
-			if (QSysInfo::WindowsVersion < QSysInfo::WV_WINDOWS7) {
+            #if QT_VERSION_MAJOR < 6
+            if (QSysInfo::WindowsVersion < QSysInfo::WV_WINDOWS7) {
+            #else
+            if (QOperatingSystemVersion::current() < QOperatingSystemVersion::Windows7) {
+            #endif
 				mplayer_bin= "mplayer/mplayer.exe";
-			}
+            }
 			#else
 			use_audio_equalizer = false;
 			initial_volnorm = false;
diff --git a/src/prefinterface.cpp b/src/prefinterface.cpp
index 1fb5f784d..5131ee871 100644
--- a/src/prefinterface.cpp
+++ b/src/prefinterface.cpp
@@ -29,6 +29,9 @@
 #include <QDir>
 #include <QStyleFactory>
 #include <QFontDialog>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#endif
 #include <QDebug>
 
 #ifdef HDPI_SUPPORT
diff --git a/src/prefperformance.cpp b/src/prefperformance.cpp
index b11d5f0e3..7944e5743 100644
--- a/src/prefperformance.cpp
+++ b/src/prefperformance.cpp
@@ -22,6 +22,9 @@
 #include "global.h"
 #include "preferences.h"
 #include "playerid.h"
+#if QT_VERSION_MAJOR >= 6
+#include <QOperatingSystemVersion>
+#endif
 
 using namespace Global;
 
@@ -51,11 +54,15 @@ PrefPerformance::PrefPerformance(QWidget * parent, Qt::WindowFlags f)
 	#ifdef Q_OS_WIN
 	hwdec_combo->addItem("dxva2", "dxva2");
 	hwdec_combo->addItem("dxva2-copy", "dxva2-copy");
-	if (QSysInfo::WindowsVersion >= QSysInfo::WV_WINDOWS8) {
-		// Windows 8+
+    #if QT_VERSION_MAJOR < 6
+    if (QSysInfo::WindowsVersion >= QSysInfo::WV_WINDOWS8) {
+    #else
+    if (QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows8) {
+    #endif
+        // Windows 8+
 		hwdec_combo->addItem("d3d11va", "d3d11va");
 		hwdec_combo->addItem("d3d11va-copy", "d3d11va-copy");
-	}
+    }
 	#endif
 	hwdec_combo->addItem("nvdec", "nvdec");
 	hwdec_combo->addItem("nvdec-copy", "nvdec-copy");
diff --git a/src/qtsingleapplication/qtlocalpeer.cpp b/src/qtsingleapplication/qtlocalpeer.cpp
index c7ce52762..fdfae383a 100644
--- a/src/qtsingleapplication/qtlocalpeer.cpp
+++ b/src/qtsingleapplication/qtlocalpeer.cpp
@@ -43,6 +43,9 @@
 #include <QCoreApplication>
 #include <QDataStream>
 #include <QTime>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegularExpression>
+#endif
 
 #if defined(Q_OS_WIN)
 #include <QLibrary>
@@ -78,7 +81,11 @@ QtLocalPeer::QtLocalPeer(QObject* parent, const QString &appId)
 #endif
         prefix = id.section(QLatin1Char('/'), -1);
     }
+#if QT_VERSION_MAJOR < 6
     prefix.remove(QRegExp("[^a-zA-Z]"));
+#else
+    prefix.remove(QRegularExpression("[^a-zA-Z]"));
+#endif
     prefix.truncate(6);
 
     QByteArray idc = id.toUtf8();
diff --git a/src/smplayer.cpp b/src/smplayer.cpp
index 6269a5613..c4b16b28e 100644
--- a/src/smplayer.cpp
+++ b/src/smplayer.cpp
@@ -46,6 +46,9 @@
 #include <QDir>
 #include <QUrl>
 #include <QTime>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#endif
 #include <stdio.h>
 
 #ifdef Q_OS_WIN
@@ -580,8 +583,9 @@ void SMPlayer::createFontFile() {
 
 void SMPlayer::showInfo() {
 #ifdef Q_OS_WIN
-	QString win_ver;
-	switch (QSysInfo::WindowsVersion) {
+#if QT_VERSION_MAJOR < 6
+    QString win_ver;
+    switch (QSysInfo::WindowsVersion) {
 		case QSysInfo::WV_2000: win_ver = "Windows 2000"; break;
 		case QSysInfo::WV_XP: win_ver = "Windows XP"; break;
 		case QSysInfo::WV_2003: win_ver = "Windows XP Professional x64/Server 2003"; break;
@@ -601,6 +605,9 @@ void SMPlayer::showInfo() {
 		case QSysInfo::WV_NT_based: win_ver = "NT-based Windows"; break;
 		default: win_ver = QString("Unknown/Unsupported Windows OS"); break;
 	}
+#else
+    QString win_ver("Windows " + QSysInfo::productVersion());
+#endif
 #endif
 	QString s = QObject::tr("This is SMPlayer v. %1 running on %2")
            .arg(Version::printable())
diff --git a/src/smplayer.pro b/src/smplayer.pro
index 8389f4981..2d24ba425 100644
--- a/src/smplayer.pro
+++ b/src/smplayer.pro
@@ -1,8 +1,8 @@
 TEMPLATE = app
 LANGUAGE = C++
 
-CONFIG += qt warn_on
-CONFIG += release
+CONFIG += qt warn_on lrelease
+#CONFIG += release
 #CONFIG += debug
 
 QT += network xml
@@ -61,6 +61,25 @@ greaterThan(QT_MAJOR_VERSION, 4):greaterThan(QT_MINOR_VERSION, 3) {
 
 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x050F00
 
+win32 {
+    CONFIG(debug, debug|release) {
+        BUILD_SUBDIR = debug
+    } else {
+        BUILD_SUBDIR = release
+    }
+    QM_SRC_DIR = $${OUT_PWD}/$${BUILD_SUBDIR}
+    QM_DST_DIR = $${OUT_PWD}/$${BUILD_SUBDIR}/translations
+    QMAKE_POST_LINK += $$quote(cmd /c if not exist $$shell_quote($$replace(QM_DST_DIR,"/","\\")) mkdir $$shell_quote($$replace(QM_DST_DIR,"/","\\")))$$escape_expand(\n\t)
+    QMAKE_POST_LINK += $$quote(cmd /c copy /y $$shell_quote($$replace(QM_SRC_DIR,"/","\\")\\)*.qm $$shell_quote($$replace(QM_DST_DIR,"/","\\")))$$escape_expand(\n\t)
+    QMAKE_CLEAN += $${QM_DST_DIR}/*.qm
+} else {
+    QM_SRC_DIR = $${OUT_PWD}
+    QM_DST_DIR = $${OUT_PWD}/translations
+    QMAKE_POST_LINK += mkdir -p $${QM_DST_DIR}$$escape_expand(\n\t)
+    QMAKE_POST_LINK += cp $${QM_SRC_DIR}/*.qm $${QM_DST_DIR}$$escape_expand(\n\t)
+    QMAKE_CLEAN += $${QM_DST_DIR}/*.qm
+}
+
 contains( DEFINES, SIMPLE_BUILD ) {
 	DEFINES -= SINGLE_INSTANCE
 	DEFINES -= FIND_SUBTITLES
@@ -259,6 +278,7 @@ HEADERS += guiconfig.h \
 	clhelp.h \
 	cleanconfig.h \
 	smplayer.h \
+	svn_revision.h \
 	myapplication.h
 
 
@@ -416,7 +436,8 @@ contains( DEFINES, FIND_SUBTITLES ) {
 	SOURCES += findsubtitles/qrestapi/qRestAPI.cpp findsubtitles/qrestapi/qRestResult.cpp \
                findsubtitles/qrestapi/qGirderAPI.cpp findsubtitles/osclient.cpp
 
-	isEqual(QT_MAJOR_VERSION, 5) {
+        I
+	greaterThan(QT_MAJOR_VERSION, 4) {
 		QT += qml
 	} else {
 		QT += script
@@ -639,10 +660,6 @@ contains( DEFINES, USE_SHM|USE_COREVIDEO_BUFFER ) {
 		LIBS += -framework Cocoa
 	}
 
-	isEqual(QT_MAJOR_VERSION, 5) {
-		#DEFINES += USE_GL_WINDOW
-	}
-
 	contains( DEFINES, USE_GL_WINDOW ) {
 		HEADERS += openglrenderer.h
 		SOURCES += openglrenderer.cpp
@@ -663,7 +680,7 @@ contains( DEFINES, USE_SHM|USE_COREVIDEO_BUFFER ) {
 
 contains(DEFINES, USE_SMTUBE_LIB) {
 	LIBS += -L../smtube -lsmtube
-	isEqual(QT_MAJOR_VERSION, 5) {
+	greaterThan(QT_MAJOR_VERSION, 4) {
 		QT += webkitwidgets widgets gui
 	} else {
 		QT += webkit
@@ -773,4 +790,3 @@ TRANSLATIONS = translations/smplayer_es.ts translations/smplayer_es_ES.ts \
                translations/smplayer_sq_AL.ts translations/smplayer_am.ts \
                translations/smplayer_fa.ts translations/smplayer_en_US.ts \
                translations/smplayer_nb_NO.ts
-
diff --git a/src/subreader.cpp b/src/subreader.cpp
index f5f696ce9..c29910d0a 100644
--- a/src/subreader.cpp
+++ b/src/subreader.cpp
@@ -26,7 +26,11 @@
 
 #define NL QString("\r\n")
 #define BNL QByteArray("\r\n")
+#if QT_VERSION_MAJOR < 6
 #define BOM QString(0xFEFF)
+#else
+#define BOM QString(QByteArray('0xFE', '0xFF'))
+#endif
 
 SubReader::SubReader() {
 	input_codec = "ISO-8859-1";
diff --git a/src/winfileassoc.cpp b/src/winfileassoc.cpp
index 1404da6e4..7707b473e 100644
--- a/src/winfileassoc.cpp
+++ b/src/winfileassoc.cpp
@@ -40,6 +40,9 @@
 #include <QSettings>
 #include <QApplication>
 #include <QFileInfo>
+#if QT_VERSION_MAJOR >= 6
+#include <QOperatingSystemVersion>
+#endif
 #include <windows.h>
 
 WinFileAssoc::WinFileAssoc(const QString ClassId, const QString AppName)
@@ -53,7 +56,11 @@ WinFileAssoc::WinFileAssoc(const QString ClassId, const QString AppName)
 // Returns number of extensions processed successfully.
 int WinFileAssoc::CreateFileAssociations(const QStringList &fileExtensions)
 {
+#if QT_VERSION_MAJOR < 6
     if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA) {
+#else
+    if (QOperatingSystemVersion::current() >= QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 }) {
+#endif
         return VistaSetAppsAsDefault(fileExtensions);
     }
 
@@ -122,7 +129,11 @@ bool WinFileAssoc::GetRegisteredExtensions(const QStringList &extensionsToCheck,
 {
     registeredExtensions.clear();
 
+#if QT_VERSION_MAJOR < 6
     if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA) {
+#else
+    if (QOperatingSystemVersion::current() >= QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 }) {
+#endif
         return VistaGetDefaultApps(extensionsToCheck, registeredExtensions);
     }
 
@@ -170,7 +181,11 @@ bool WinFileAssoc::GetRegisteredExtensions(const QStringList &extensionsToCheck,
 // Returns number of extensions successfully processed (error if fileExtensions.count() != return value && count > 0).
 int WinFileAssoc::RestoreFileAssociations(const QStringList &fileExtensions)
 {
+#if QT_VERSION_MAJOR < 6
     if (QSysInfo::WindowsVersion >= QSysInfo::WV_VISTA)
+#else
+    if (QOperatingSystemVersion::current() >= QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 })
+#endif
         return 0; // Not supported by the API
 
     QSettings RegCR("HKEY_CLASSES_ROOT", QSettings::NativeFormat);
diff --git a/src/winscreensaver.cpp b/src/winscreensaver.cpp
index 2b104c8db..5ed960c3a 100644
--- a/src/winscreensaver.cpp
+++ b/src/winscreensaver.cpp
@@ -16,8 +16,12 @@
     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
 
-#include <Qt>
 #include <QSysInfo>
+#if QT_VERSION_MAJOR < 6
+#include <Qt>
+#else
+#include <QOperatingSystemVersion>
+#endif
 #include "winscreensaver.h"
 #ifndef Q_OS_OS2
 #include <windows.h>
@@ -53,7 +57,11 @@ void WinScreenSaver::retrieveState() {
 	
 	if (!state_saved) {
 #ifndef Q_OS_OS2
+#if QT_VERSION_MAJOR < 6
 		if (QSysInfo::WindowsVersion < QSysInfo::WV_VISTA) {
+#else
+        if (QOperatingSystemVersion::current() < QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 }) {
+#endif
 			// Not supported on Windows Vista
 			SystemParametersInfo(SPI_GETLOWPOWERTIMEOUT, 0, &lowpower, 0);
 			SystemParametersInfo(SPI_GETPOWEROFFTIMEOUT, 0, &poweroff, 0);
@@ -79,8 +87,12 @@ void WinScreenSaver::restoreState() {
 	
 	if (state_saved) {
 #ifndef Q_OS_OS2
-		if (QSysInfo::WindowsVersion < QSysInfo::WV_VISTA) {
-			// Not supported on Windows Vista
+#if QT_VERSION_MAJOR < 6
+        if (QSysInfo::WindowsVersion < QSysInfo::WV_VISTA) {
+#else
+        if (QOperatingSystemVersion::current() < QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 }) {
+#endif
+            // Not supported on Windows Vista
 			SystemParametersInfo(SPI_SETLOWPOWERTIMEOUT, lowpower, NULL, 0);
 			SystemParametersInfo(SPI_SETPOWEROFFTIMEOUT, poweroff, NULL, 0);
 		}
@@ -112,8 +124,12 @@ void WinScreenSaver::disable() {
 	qDebug("WinScreenSaver::disable");
 
 #ifndef Q_OS_OS2
-	if (QSysInfo::WindowsVersion < QSysInfo::WV_VISTA) {
-		// Not supported on Windows Vista
+#if QT_VERSION_MAJOR < 6
+    if (QSysInfo::WindowsVersion < QSysInfo::WV_VISTA) {
+#else
+    if (QOperatingSystemVersion::current() < QOperatingSystemVersionBase{ QOperatingSystemVersionBase::Windows, 6, 0 }) {
+#endif
+        // Not supported on Windows Vista
 		SystemParametersInfo(SPI_SETLOWPOWERTIMEOUT, 0, NULL, 0);
 		SystemParametersInfo(SPI_SETPOWEROFFTIMEOUT, 0, NULL, 0);
 	}
diff --git a/src/winscreensaver.h b/src/winscreensaver.h
index 1c80095ab..91fb66dc2 100644
--- a/src/winscreensaver.h
+++ b/src/winscreensaver.h
@@ -24,9 +24,11 @@
 #ifdef Q_OS_OS2
 #include <QLibrary>
 #else
+#if QT_VERSION_MAJOR < 6
 #undef _WIN32_WINNT
 #define _WIN32_WINNT 0x0501
 #endif
+#endif
 
 class WinScreenSaver
 {
diff --git a/src/youtube/codedownloader.cpp b/src/youtube/codedownloader.cpp
index 9bc1c95aa..c25b31fb2 100644
--- a/src/youtube/codedownloader.cpp
+++ b/src/youtube/codedownloader.cpp
@@ -20,6 +20,9 @@
 #include "retrieveyoutubeurl.h"
 #include <QFile>
 #include <QMessageBox>
+#if QT_VERSION_MAJOR >= 6
+#include <QRegExp>
+#endif
 #include <QDebug>
 
 #include <QDir>
diff --git a/webserver/mongoose.h b/webserver/mongoose.h
index cd1d92c3d..3e92b883f 100644
--- a/webserver/mongoose.h
+++ b/webserver/mongoose.h
@@ -210,7 +210,7 @@
 #include <windows.h>
 #include <process.h>
 
-#if _MSC_VER < 1700
+#if defined( _MSC_VER ) && _MSC_VER < 1700
 typedef int bool;
 #else
 #include <stdbool.h>