diff --git a/gpxsee.pro b/gpxsee.pro
index b59722c1..b1a5179e 100644
--- a/gpxsee.pro
+++ b/gpxsee.pro
@@ -18,8 +18,10 @@ QT += core \
     svg \
     serialport
 greaterThan(QT_MAJOR_VERSION, 5) {
-    QT += openglwidgets \
-          core5compat
+    QT += openglwidgets
+	lessThan(QT_MINOR_VERSION, 5) {
+	    QT += core5compat
+	}
 }
 
 CONFIG += object_parallel_to_source
diff --git a/src/common/textcodec.cpp b/src/common/textcodec.cpp
index 36b66ff5..46f9709d 100644
--- a/src/common/textcodec.cpp
+++ b/src/common/textcodec.cpp
@@ -1,6 +1,7 @@
-#include <QTextCodec>
 #include "textcodec.h"
 
+#if QT_VERSION < QT_VERSION_CHECK(6, 5, 0)
+
 static QTextCodec *codec(int mib)
 {
 	QTextCodec *c = QTextCodec::codecForMib(mib);
@@ -10,6 +11,10 @@ static QTextCodec *codec(int mib)
 	return c;
 }
 
+TextCodec::TextCodec() : _codec(0)
+{
+}
+
 TextCodec::TextCodec(int codepage)
 {
 	switch (codepage) {
@@ -64,7 +69,30 @@ TextCodec::TextCodec(int codepage)
 	}
 }
 
-QString TextCodec::toString(const QByteArray &ba) const
+QString TextCodec::toString(const QByteArray &ba)
 {
 	return _codec ? _codec->toUnicode(ba) : QString::fromUtf8(ba);
 }
+
+#else // QT 6.5
+
+TextCodec::TextCodec()
+{
+}
+
+TextCodec::TextCodec(int codepage)
+{
+	if (codepage != 65001) {
+		QByteArray cp(QByteArray("CP") + QByteArray::number(codepage));
+		_decoder = QStringDecoder(cp.constData());
+
+		if (!_decoder.isValid())
+			qWarning("%d: Unknown codepage, using UTF-8", codepage);
+	}
+}
+
+QString TextCodec::toString(const QByteArray &ba)
+{
+	return _decoder.isValid() ? _decoder.decode(ba) : QString::fromUtf8(ba);
+}
+#endif // QT 6.5
diff --git a/src/common/textcodec.h b/src/common/textcodec.h
index 9cb68067..7dd9cb25 100644
--- a/src/common/textcodec.h
+++ b/src/common/textcodec.h
@@ -3,19 +3,26 @@
 
 #include <QString>
 #include <QMap>
-
-class QTextCodec;
+#if QT_VERSION < QT_VERSION_CHECK(6, 5, 0)
+#include <QTextCodec>
+#else // QT 6.5
+#include <QStringDecoder>
+#endif // QT 6.5
 
 class TextCodec
 {
 public:
-	TextCodec() : _codec(0) {}
+	TextCodec();
 	TextCodec(int codepage);
 
-	QString toString(const QByteArray &ba) const;
+	QString toString(const QByteArray &ba);
 
 private:
+#if QT_VERSION < QT_VERSION_CHECK(6, 5, 0)
 	QTextCodec *_codec;
+#else // QT 6.5
+	QStringDecoder _decoder;
+#endif // QT 6.5
 };
 
 #endif // TEXTCODEC_H
diff --git a/src/map/IMG/lblfile.cpp b/src/map/IMG/lblfile.cpp
index 9f29e394..0975a792 100644
--- a/src/map/IMG/lblfile.cpp
+++ b/src/map/IMG/lblfile.cpp
@@ -138,7 +138,7 @@ void LBLFile::clear()
 }
 
 Label LBLFile::str2label(const QVector<quint8> &str, bool capitalize,
-  bool convert) const
+  bool convert)
 {
 	Shield::Type shieldType = Shield::None;
 	QByteArray label, shieldLabel;
@@ -247,7 +247,7 @@ Label LBLFile::label6b(const SubFile *file, Handle &fileHdl, quint32 size,
 }
 
 Label LBLFile::label8b(const SubFile *file, Handle &fileHdl, quint32 size,
-  bool capitalize, bool convert) const
+  bool capitalize, bool convert)
 {
 	QVector<quint8> str;
 	quint8 c;
@@ -264,7 +264,7 @@ Label LBLFile::label8b(const SubFile *file, Handle &fileHdl, quint32 size,
 }
 
 Label LBLFile::labelHuffman(Handle &hdl, const SubFile *file, Handle &fileHdl,
-  quint32 size, bool capitalize, bool convert) const
+  quint32 size, bool capitalize, bool convert)
 {
 	QVector<quint8> str;
 
@@ -305,7 +305,7 @@ Label LBLFile::labelHuffman(Handle &hdl, const SubFile *file, Handle &fileHdl,
 }
 
 Label LBLFile::label(Handle &hdl, quint32 offset, bool poi, bool capitalize,
-  bool convert) const
+  bool convert)
 {
 	quint32 labelOffset;
 	if (poi) {
@@ -328,7 +328,7 @@ Label LBLFile::label(Handle &hdl, quint32 offset, bool poi, bool capitalize,
 }
 
 Label LBLFile::label(Handle &hdl, const SubFile *file, Handle &fileHdl,
-  quint32 size, bool capitalize, bool convert) const
+  quint32 size, bool capitalize, bool convert)
 {
 	switch (_encoding) {
 		case 6:
diff --git a/src/map/IMG/lblfile.h b/src/map/IMG/lblfile.h
index e3a01201..0203257a 100644
--- a/src/map/IMG/lblfile.h
+++ b/src/map/IMG/lblfile.h
@@ -30,9 +30,9 @@ public:
 	void clear();
 
 	Label label(Handle &hdl, quint32 offset, bool poi = false,
-	  bool capitalize = true, bool convert = false) const;
+	  bool capitalize = true, bool convert = false);
 	Label label(Handle &hdl, const SubFile *file, Handle &fileHdl,
-	  quint32 size, bool capitalize = true, bool convert = false) const;
+	  quint32 size, bool capitalize = true, bool convert = false);
 
 	quint8 imageIdSize() const {return _imgIdSize;}
 	QPixmap image(Handle &hdl, quint32 id) const;
@@ -44,13 +44,13 @@ private:
 	};
 
 	Label str2label(const QVector<quint8> &str, bool capitalize,
-	  bool convert) const;
+	  bool convert);
 	Label label6b(const SubFile *file, Handle &fileHdl, quint32 size,
 	  bool capitalize, bool convert) const;
 	Label label8b(const SubFile *file, Handle &fileHdl, quint32 size,
-	  bool capitalize, bool convert) const;
+	  bool capitalize, bool convert);
 	Label labelHuffman(Handle &hdl, const SubFile *file, Handle &fileHdl,
-	  quint32 size, bool capitalize, bool convert) const;
+	  quint32 size, bool capitalize, bool convert);
 	bool loadRasterTable(Handle &hdl, quint32 offset, quint32 size,
 	  quint32 recordSize);
 
diff --git a/src/map/IMG/netfile.cpp b/src/map/IMG/netfile.cpp
index 9d5a603a..e37b27fe 100644
--- a/src/map/IMG/netfile.cpp
+++ b/src/map/IMG/netfile.cpp
@@ -329,7 +329,7 @@ bool NETFile::readShape(const NODFile *nod, SubFile::Handle &nodHdl,
 }
 
 bool NETFile::linkLabel(Handle &hdl, quint32 offset,
-  const LBLFile *lbl, Handle &lblHdl, Label &label) const
+  LBLFile *lbl, Handle &lblHdl, Label &label) const
 {
 	if (!seek(hdl, offset))
 		return false;
@@ -392,7 +392,7 @@ NETFile::~NETFile()
 }
 
 bool NETFile::link(const SubDiv *subdiv, quint32 shift, Handle &hdl,
-  const NODFile *nod, Handle &nodHdl2, Handle &nodHdl, const LBLFile *lbl,
+  const NODFile *nod, Handle &nodHdl2, Handle &nodHdl, LBLFile *lbl,
   Handle &lblHdl, const NODFile::BlockInfo &blockInfo, quint8 linkId,
   quint8 lineId, QList<MapData::Poly> *lines) const
 {
diff --git a/src/map/IMG/netfile.h b/src/map/IMG/netfile.h
index a1fb4735..bf63a0de 100644
--- a/src/map/IMG/netfile.h
+++ b/src/map/IMG/netfile.h
@@ -30,13 +30,13 @@ public:
 
 	bool lblOffset(Handle &hdl, quint32 netOffset, quint32 &lblOffset) const;
 	bool link(const SubDiv *subdiv, quint32 shift, Handle &hdl,
-	  const NODFile *nod, Handle &nodHdl2, Handle &nodHdl, const LBLFile *lbl,
+	  const NODFile *nod, Handle &nodHdl2, Handle &nodHdl, LBLFile *lbl,
 	  Handle &lblHdl, const NODFile::BlockInfo &blockInfo, quint8 linkId,
 	  quint8 lineId, QList<MapData::Poly> *lines) const;
 	bool hasLinks() const {return (_links.size > 0);}
 
 private:
-	bool linkLabel(Handle &hdl, quint32 offset, const LBLFile *lbl,
+	bool linkLabel(Handle &hdl, quint32 offset, LBLFile *lbl,
 	  Handle &lblHdl, Label &label) const;
 	bool readShape(const NODFile *nod, SubFile::Handle &nodHdl,
 	  NODFile::AdjacencyInfo &adj, BitStream4R &bs, const SubDiv *subdiv,
diff --git a/src/map/IMG/rgnfile.cpp b/src/map/IMG/rgnfile.cpp
index ae7a7f81..0de976ba 100644
--- a/src/map/IMG/rgnfile.cpp
+++ b/src/map/IMG/rgnfile.cpp
@@ -107,7 +107,7 @@ bool RGNFile::readObstructionInfo(Handle &hdl, quint8 flags, quint32 size,
 	return true;
 }
 
-bool RGNFile::readLabel(Handle &hdl, const LBLFile *lbl, Handle &lblHdl,
+bool RGNFile::readLabel(Handle &hdl, LBLFile *lbl, Handle &lblHdl,
   quint8 flags, quint32 size, MapData::Point *point) const
 {
 	if (!(flags & 1))
@@ -122,7 +122,7 @@ bool RGNFile::readLabel(Handle &hdl, const LBLFile *lbl, Handle &lblHdl,
 }
 
 bool RGNFile::readClassFields(Handle &hdl, SegmentType segmentType,
-  void *object, const LBLFile *lbl, Handle &lblHdl) const
+  void *object, LBLFile *lbl, Handle &lblHdl) const
 {
 	quint8 flags;
 	quint32 rs = 0;
@@ -257,7 +257,7 @@ void RGNFile::clear()
 }
 
 bool RGNFile::polyObjects(Handle &hdl, const SubDiv *subdiv,
-  SegmentType segmentType, const LBLFile *lbl, Handle &lblHdl, NETFile *net,
+  SegmentType segmentType, LBLFile *lbl, Handle &lblHdl, NETFile *net,
   Handle &netHdl, QList<MapData::Poly> *polys) const
 {
 	const SubDiv::Segment &segment = (segmentType == Line)
@@ -340,7 +340,7 @@ bool RGNFile::polyObjects(Handle &hdl, const SubDiv *subdiv,
 }
 
 bool RGNFile::extPolyObjects(Handle &hdl, const SubDiv *subdiv, quint32 shift,
-  SegmentType segmentType, const LBLFile *lbl, Handle &lblHdl,
+  SegmentType segmentType, LBLFile *lbl, Handle &lblHdl,
   QList<MapData::Poly> *polys) const
 {
 	quint32 labelPtr, len;
@@ -457,7 +457,7 @@ bool RGNFile::extPolyObjects(Handle &hdl, const SubDiv *subdiv, quint32 shift,
 }
 
 bool RGNFile::pointObjects(Handle &hdl, const SubDiv *subdiv,
-  SegmentType segmentType, const LBLFile *lbl, Handle &lblHdl,
+  SegmentType segmentType, LBLFile *lbl, Handle &lblHdl,
   QList<MapData::Point> *points) const
 {
 	const SubDiv::Segment &segment = (segmentType == IndexedPoint)
@@ -502,7 +502,7 @@ bool RGNFile::pointObjects(Handle &hdl, const SubDiv *subdiv,
 }
 
 bool RGNFile::extPointObjects(Handle &hdl, const SubDiv *subdiv,
-  const LBLFile *lbl, Handle &lblHdl, QList<MapData::Point> *points) const
+  LBLFile *lbl, Handle &lblHdl, QList<MapData::Point> *points) const
 {
 	const SubDiv::Segment &segment = subdiv->extPoints();
 
@@ -554,7 +554,7 @@ bool RGNFile::extPointObjects(Handle &hdl, const SubDiv *subdiv,
 
 bool RGNFile::links(Handle &hdl, const SubDiv *subdiv, quint32 shift,
   const NETFile *net, Handle &netHdl, const NODFile *nod, Handle &nodHdl,
-  Handle &nodHdl2, const LBLFile *lbl, Handle &lblHdl,
+  Handle &nodHdl2, LBLFile *lbl, Handle &lblHdl,
   QList<MapData::Poly> *lines) const
 {
 	quint32 size, blockIndexId;
diff --git a/src/map/IMG/rgnfile.h b/src/map/IMG/rgnfile.h
index 87836dbb..528e94a0 100644
--- a/src/map/IMG/rgnfile.h
+++ b/src/map/IMG/rgnfile.h
@@ -33,18 +33,18 @@ public:
 	bool load(Handle &hdl);
 
 	bool polyObjects(Handle &hdl, const SubDiv *subdiv, SegmentType segmentType,
-	  const LBLFile *lbl, Handle &lblHdl, NETFile *net, Handle &netHdl,
+	  LBLFile *lbl, Handle &lblHdl, NETFile *net, Handle &netHdl,
 	  QList<MapData::Poly> *polys) const;
 	bool pointObjects(Handle &hdl, const SubDiv *subdiv, SegmentType segmentType,
-	  const LBLFile *lbl, Handle &lblHdl, QList<MapData::Point> *points) const;
+	  LBLFile *lbl, Handle &lblHdl, QList<MapData::Point> *points) const;
 	bool extPolyObjects(Handle &hdl, const SubDiv *subdiv, quint32 shift,
-	  SegmentType segmentType, const LBLFile *lbl, Handle &lblHdl,
+	  SegmentType segmentType, LBLFile *lbl, Handle &lblHdl,
 	  QList<MapData::Poly> *polys) const;
-	bool extPointObjects(Handle &hdl, const SubDiv *subdiv, const LBLFile *lbl,
+	bool extPointObjects(Handle &hdl, const SubDiv *subdiv, LBLFile *lbl,
 	  Handle &lblHdl, QList<MapData::Point> *points) const;
 	bool links(Handle &hdl, const SubDiv *subdiv, quint32 shift,
 	  const NETFile *net, Handle &netHdl, const NODFile *nod, Handle &nodHdl,
-	  Handle &nodHdl2, const LBLFile *lbl, Handle &lblHdl,
+	  Handle &nodHdl2, LBLFile *lbl, Handle &lblHdl,
 	  QList<MapData::Poly> *lines) const;
 
 	bool subdivInit(Handle &hdl, SubDiv *subdiv) const;
@@ -55,7 +55,7 @@ public:
 private:
 	bool segments(Handle &hdl, SubDiv *subdiv, SubDiv::Segment seg[5]) const;
 	bool readClassFields(Handle &hdl, SegmentType segmentType, void *object,
-	  const LBLFile *lbl, Handle &lblHdl) const;
+	  LBLFile *lbl, Handle &lblHdl) const;
 	bool skipLclFields(Handle &hdl, const quint32 flags[3]) const;
 	bool skipGblFields(Handle &hdl, quint32 flags) const;
 	bool readRasterInfo(Handle &hdl, const LBLFile *lbl, quint32 size,
@@ -64,7 +64,7 @@ private:
 	  MapData::Point *point) const;
 	bool readObstructionInfo(Handle &hdl, quint8 flags, quint32 size,
 	  MapData::Point *point) const;
-	bool readLabel(Handle &hdl, const LBLFile *lbl, Handle &lblHdl,
+	bool readLabel(Handle &hdl, LBLFile *lbl, Handle &lblHdl,
 	  quint8 flags, quint32 size, MapData::Point *point) const;
 
 	HuffmanTable *_huffmanTable;