diff --git a/BUILD.md b/BUILD.md
index 12dfe9a2..47cede3c 100644
--- a/BUILD.md
+++ b/BUILD.md
@@ -1,6 +1,6 @@
 # General Development Notes
 
-Red Panda C++ need Qt 5.15 to build.
+Red Panda C++ need Qt 5.15 or 6.7+ to build.
 
 Recommended development environments:
 1. Visual Studio Code.
diff --git a/BUILD_cn.md b/BUILD_cn.md
index a8cee914..f8e7967a 100644
--- a/BUILD_cn.md
+++ b/BUILD_cn.md
@@ -1,6 +1,6 @@
 # 通用开发说明
 
-小熊猫C++ 需要 Qt 5.15。
+小熊猫C++ 需要 Qt 5.15 或 6.7+。
 
 推荐开发环境：
 1. Visual Studio Code。
diff --git a/RedPandaIDE/compiler/compiler.cpp b/RedPandaIDE/compiler/compiler.cpp
index fe0a5ce9..e8ef1640 100644
--- a/RedPandaIDE/compiler/compiler.cpp
+++ b/RedPandaIDE/compiler/compiler.cpp
@@ -25,7 +25,6 @@
 #include <QFileInfo>
 #include <QProcess>
 #include <QString>
-#include <QTextCodec>
 #include <QTime>
 #include <QApplication>
 #include "../editor.h"
diff --git a/RedPandaIDE/compiler/stdincompiler.cpp b/RedPandaIDE/compiler/stdincompiler.cpp
index ba4ed54f..66ceec5e 100644
--- a/RedPandaIDE/compiler/stdincompiler.cpp
+++ b/RedPandaIDE/compiler/stdincompiler.cpp
@@ -18,7 +18,6 @@
 #include "compilermanager.h"
 #include <QFile>
 #include <QFileInfo>
-#include <QTextCodec>
 
 StdinCompiler::StdinCompiler(const QString &filename,const QByteArray& encoding, const QString& content, bool onlyCheckSyntax):
     Compiler(filename, onlyCheckSyntax),
@@ -98,9 +97,9 @@ QByteArray StdinCompiler::pipedText()
     if (mEncoding == ENCODING_ASCII)
         return mContent.toLatin1();
 
-    QTextCodec* codec = QTextCodec::codecForName(mEncoding);
-    if (codec) {
-        return codec->fromUnicode(mContent);
+    TextEncoder encoder(mEncoding);
+    if (encoder.isValid()) {
+        return encoder.encodeUnchecked(mContent);
     } else {
         return mContent.toLocal8Bit();
     }
diff --git a/RedPandaIDE/cpprefacter.cpp b/RedPandaIDE/cpprefacter.cpp
index 5a62af36..3716834f 100644
--- a/RedPandaIDE/cpprefacter.cpp
+++ b/RedPandaIDE/cpprefacter.cpp
@@ -17,7 +17,6 @@
 #include <QFile>
 #include <QMessageBox>
 #include <QProgressDialog>
-#include <QTextCodec>
 #include <qsynedit/document.h>
 #include "cpprefacter.h"
 #include "mainwindow.h"
diff --git a/RedPandaIDE/debugger/debugger.cpp b/RedPandaIDE/debugger/debugger.cpp
index 7a33ae22..e4954044 100644
--- a/RedPandaIDE/debugger/debugger.cpp
+++ b/RedPandaIDE/debugger/debugger.cpp
@@ -2542,11 +2542,8 @@ QVariant MemoryModel::data(const QModelIndex &index, int role) const
     if (role == Qt::DisplayRole) {
         if (col==line->datas.count()) {
             QString s;
-            foreach (unsigned char ch, line->datas) {
-                if (ch<' ' || ch>=128)
-                    s+='.';
-                else
-                    s+=ch;
+            for (char ch : line->datas) {
+                s += isAsciiPrint(ch) ? ch : '.';
             }
             return s;
         } else
diff --git a/RedPandaIDE/editor.cpp b/RedPandaIDE/editor.cpp
index bb02cae1..5f5c5e41 100644
--- a/RedPandaIDE/editor.cpp
+++ b/RedPandaIDE/editor.cpp
@@ -18,7 +18,6 @@
 
 #include <QtCore/QFileInfo>
 #include <QFont>
-#include <QTextCodec>
 #include <QVariant>
 #include <QWheelEvent>
 #include <QGuiApplication>
@@ -30,7 +29,6 @@
 #include <QPrinter>
 #include <QPrintDialog>
 #include <QTextDocument>
-#include <QTextCodec>
 #include <QScrollBar>
 #include <QScreen>
 #include <memory>
@@ -4230,7 +4228,7 @@ void Editor::updateFunctionTip(bool showTip)
         return;
 
     QChar ch=lastNonSpaceChar(currentLine,currentChar);
-    if (ch!="(" && ch!=",")
+    if (ch!='(' && ch!=',')
         return;
 
     QSynedit::PTokenAttribute attr;
diff --git a/RedPandaIDE/main.cpp b/RedPandaIDE/main.cpp
index 0789cf08..48b31627 100644
--- a/RedPandaIDE/main.cpp
+++ b/RedPandaIDE/main.cpp
@@ -59,7 +59,11 @@ class WindowLogoutEventFilter : public QAbstractNativeEventFilter {
 
     // QAbstractNativeEventFilter interface
 public:
+#if QT_VERSION_MAJOR >= 6
+    bool nativeEventFilter(const QByteArray &eventType, void *message, qintptr *result) override;
+#else
     bool nativeEventFilter(const QByteArray &eventType, void *message, long *result) override;
+#endif
 };
 
 #ifndef WM_DPICHANGED
@@ -124,7 +128,12 @@ HWND getPreviousInstance() {
         return NULL;
 }
 
-bool WindowLogoutEventFilter::nativeEventFilter(const QByteArray & /*eventType*/, void *message, long *result){
+#if QT_VERSION_MAJOR >= 6
+bool WindowLogoutEventFilter::nativeEventFilter(const QByteArray & /*eventType*/, void *message, qintptr *result)
+#else
+bool WindowLogoutEventFilter::nativeEventFilter(const QByteArray & /*eventType*/, void *message, long *result)
+#endif
+{
     MSG * pMsg = static_cast<MSG *>(message);
     switch(pMsg->message) {
     case WM_QUERYENDSESSION:
diff --git a/RedPandaIDE/mainwindow.cpp b/RedPandaIDE/mainwindow.cpp
index 6efc4738..b2bda0a0 100644
--- a/RedPandaIDE/mainwindow.cpp
+++ b/RedPandaIDE/mainwindow.cpp
@@ -17,7 +17,6 @@
 #include <QGuiApplication>
 #include <QClipboard>
 #include <QMessageBox>
-#include <QTextCodec>
 #include <QCloseEvent>
 #include <QComboBox>
 #include <QDesktopServices>
@@ -45,6 +44,7 @@
 #include <QUuid>
 #include <QScrollBar>
 #include <QTextDocumentFragment>
+#include <QActionGroup>
 
 #include "mainwindow.h"
 #include "ui_mainwindow.h"
@@ -1733,7 +1733,7 @@ Editor* MainWindow::openFile(QString filename, bool activate, QTabWidget* page)
         }
         bool inProject = (mProject && unit);
         QByteArray encoding = unit ? unit->encoding() :
-                                     (pSettings->editor().autoDetectFileEncoding()? ENCODING_AUTO_DETECT : pSettings->editor().defaultEncoding());
+                                     (pSettings->editor().autoDetectFileEncoding() ? QByteArray(ENCODING_AUTO_DETECT) : pSettings->editor().defaultEncoding());
         Project * pProject = (inProject?mProject.get():nullptr);
         if (pProject && encoding==ENCODING_PROJECT)
             encoding=pProject->options().encoding;
@@ -3449,7 +3449,7 @@ void MainWindow::loadLastOpens()
         }
         bool inProject = (mProject && unit);
         QByteArray encoding = unit ? unit->encoding() :
-                                     (pSettings->editor().autoDetectFileEncoding()? ENCODING_AUTO_DETECT : pSettings->editor().defaultEncoding());
+                                     (pSettings->editor().autoDetectFileEncoding()? QByteArray(ENCODING_AUTO_DETECT) : pSettings->editor().defaultEncoding());
         Project* pProject = (inProject?mProject.get():nullptr);
         if (pProject && encoding==ENCODING_PROJECT)
             encoding=pProject->options().encoding;
@@ -6349,7 +6349,7 @@ void MainWindow::on_actionConvert_to_ANSI_triggered()
         return;
     if (QMessageBox::warning(this,tr("Confirm Convertion"),
                    tr("The editing file will be saved using %1 encoding. <br />This operation can't be reverted. <br />Are you sure to continue?")
-                   .arg(QString(QTextCodec::codecForLocale()->name())),
+                   .arg(QString(TextEncoder::encoderForSystem().name())),
                    QMessageBox::Yes, QMessageBox::No)!=QMessageBox::Yes)
         return;
     editor->convertToEncoding(ENCODING_SYSTEM_DEFAULT);
diff --git a/RedPandaIDE/parser/cpppreprocessor.cpp b/RedPandaIDE/parser/cpppreprocessor.cpp
index 55c67b3b..60ad6038 100644
--- a/RedPandaIDE/parser/cpppreprocessor.cpp
+++ b/RedPandaIDE/parser/cpppreprocessor.cpp
@@ -17,7 +17,6 @@
 #include "cpppreprocessor.h"
 
 #include <QFile>
-#include <QTextCodec>
 #include <QDebug>
 #include <QMessageBox>
 #include "../utils.h"
diff --git a/RedPandaIDE/parser/cpptokenizer.h b/RedPandaIDE/parser/cpptokenizer.h
index dd1782c6..6514a587 100644
--- a/RedPandaIDE/parser/cpptokenizer.h
+++ b/RedPandaIDE/parser/cpptokenizer.h
@@ -113,7 +113,7 @@ private:
     }
 
     static bool isBlankChar(const QChar& ch) {
-        return (ch<=32) && (ch>0);
+        return (ch.unicode() <= 32) && (ch.unicode() > 0);
     }
 
 //    static bool isOperatorChar(const QChar& ch) {
diff --git a/RedPandaIDE/project.cpp b/RedPandaIDE/project.cpp
index 2321a281..d8d97adb 100644
--- a/RedPandaIDE/project.cpp
+++ b/RedPandaIDE/project.cpp
@@ -16,6 +16,7 @@
  */
 #include "project.h"
 #include "editor.h"
+#include "qt_utils/utils.h"
 #include "utils.h"
 #include "systemconsts.h"
 #include "editorlist.h"
@@ -31,7 +32,6 @@
 #include <QFileDialog>
 #include <QFileInfo>
 #include <QMessageBox>
-#include <QTextCodec>
 #include <QMessageBox>
 #include <QDirIterator>
 #include <QMimeDatabase>
@@ -255,7 +255,7 @@ void Project::open()
         if (newUnit->encoding()!=ENCODING_UTF16_BOM &&
                 newUnit->encoding()!=ENCODING_UTF8_BOM &&
                 newUnit->encoding()!=ENCODING_UTF32_BOM &&
-                QTextCodec::codecForName(newUnit->encoding())==nullptr) {
+                !isEncodingAvailable(newUnit->encoding())) {
             newUnit->setEncoding(ENCODING_PROJECT);
         }
         newUnit->setRealEncoding(ini.GetValue(groupName, "RealEncoding",ENCODING_ASCII));
@@ -944,11 +944,9 @@ bool Project::assignTemplate(const std::shared_ptr<ProjectTemplate> aTemplate, b
     updateCompilerSetting();
     mOptions.icon = aTemplate->icon();
 
-    QTextCodec* codec=QTextCodec::codecForName(mOptions.encoding);
-    if (!codec)
+    if (!isEncodingAvailable(mOptions.encoding))
         mOptions.encoding=ENCODING_SYSTEM_DEFAULT;
-    codec=QTextCodec::codecForName(mOptions.execEncoding);
-    if (!codec)
+    if (!isEncodingAvailable(mOptions.execEncoding))
         mOptions.execEncoding=ENCODING_SYSTEM_DEFAULT;
 
     // Copy icon to project directory
@@ -2611,7 +2609,7 @@ QVariant ProjectModel::data(const QModelIndex &index, int role) const
         if (p->isUnit) {
             PProjectUnit unit = p->pUnit.lock();
             if (unit)
-                icon = mIconProvider->icon(unit->fileName());
+                icon = mIconProvider->icon(QFileInfo(unit->fileName()));
         } else {
             if (p == mProject->rootNode().get()) {
 #ifdef ENABLE_VCS
diff --git a/RedPandaIDE/settings.cpp b/RedPandaIDE/settings.cpp
index b1e044a5..4febc731 100644
--- a/RedPandaIDE/settings.cpp
+++ b/RedPandaIDE/settings.cpp
@@ -16,7 +16,6 @@
  */
 #include "settings.h"
 #include <QApplication>
-#include <QTextCodec>
 #include <algorithm>
 #include "utils.h"
 #include "utils/escape.h"
diff --git a/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp b/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
index 59a592ca..a7cefd6a 100644
--- a/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
+++ b/RedPandaIDE/settingsdialog/projectgeneralwidget.cpp
@@ -28,7 +28,6 @@
 #include <QImageWriter>
 #include <QImageWriter>
 #include <QMessageBox>
-#include <QTextCodec>
 
 ProjectGeneralWidget::ProjectGeneralWidget(const QString &name, const QString &group, QWidget *parent) :
     SettingsWidget(name,group,parent),
diff --git a/RedPandaIDE/systemconsts.cpp b/RedPandaIDE/systemconsts.cpp
index b6602802..1fb8cddc 100644
--- a/RedPandaIDE/systemconsts.cpp
+++ b/RedPandaIDE/systemconsts.cpp
@@ -20,7 +20,6 @@
 #include <QSet>
 #include <QString>
 #include <QStringList>
-#include <QTextCodec>
 
 SystemConsts* pSystemConsts;
 
@@ -44,28 +43,7 @@ SystemConsts::SystemConsts(): mDefaultFileFilters()
     mCodecNames.append(ENCODING_SYSTEM_DEFAULT);
     mCodecNames.append(ENCODING_UTF8);
     mCodecNames.append(ENCODING_UTF8_BOM);
-    QStringList codecNames;
-    QSet<QByteArray> codecAlias;
-    codecAlias.insert("system");
-    codecAlias.insert("utf-8");
-
-    foreach (const QByteArray& name, QTextCodec::availableCodecs()){
-        QByteArray lname = name.toLower();
-        if (lname.startsWith("cp"))
-            continue;
-        if (codecAlias.contains(lname))
-            continue;
-        codecNames.append(lname);
-        codecAlias.insert(lname);
-        QTextCodec* codec = QTextCodec::codecForName(name);
-        if (codec) {
-            foreach (const QByteArray& alias, codec->aliases()) {
-                codecAlias.insert(alias.toLower());
-            }
-        }
-    }
-    std::sort(codecNames.begin(),codecNames.end());
-    mCodecNames.append(codecNames);
+    mCodecNames.append(availableEncodings());
 
     mDefaultFileNameFilters.append("*.c");
     mDefaultFileNameFilters.append("*.cpp");
diff --git a/RedPandaIDE/utils.h b/RedPandaIDE/utils.h
index ef4aac82..abd458a1 100644
--- a/RedPandaIDE/utils.h
+++ b/RedPandaIDE/utils.h
@@ -227,4 +227,12 @@ bool osSupportsUtf8Manifest();
 bool applicationIsUtf8(const QString &path);
 #endif
 
+#if QT_VERSION_MAJOR >= 6
+// for xml.name() == "tag"
+inline bool operator==(QStringView a, const char *b)
+{
+    return a.compare(b);
+}
+#endif
+
 #endif // UTILS_H
diff --git a/RedPandaIDE/widgets/coloredit.cpp b/RedPandaIDE/widgets/coloredit.cpp
index f96b862a..eccecd49 100644
--- a/RedPandaIDE/widgets/coloredit.cpp
+++ b/RedPandaIDE/widgets/coloredit.cpp
@@ -115,7 +115,11 @@ void ColorEdit::mouseReleaseEvent(QMouseEvent *)
     }
 }
 
+#if QT_VERSION_MAJOR >= 6
+void ColorEdit::enterEvent(QEnterEvent *)
+#else
 void ColorEdit::enterEvent(QEvent *)
+#endif
 {
     setCursor(Qt::PointingHandCursor);
 }
diff --git a/RedPandaIDE/widgets/coloredit.h b/RedPandaIDE/widgets/coloredit.h
index 3e8d39b2..6daa8bcb 100644
--- a/RedPandaIDE/widgets/coloredit.h
+++ b/RedPandaIDE/widgets/coloredit.h
@@ -37,7 +37,11 @@ public:
     QSize sizeHint() const override;
     void paintEvent(QPaintEvent *event) override;
     void mouseReleaseEvent(QMouseEvent *event) override;
+#if QT_VERSION_MAJOR >= 6
+    void enterEvent(QEnterEvent *event) override;
+#else
     void enterEvent(QEvent *event) override;
+#endif
     void leaveEvent(QEvent *event) override;
     QSize minimumSizeHint() const override;
 };
diff --git a/RedPandaIDE/widgets/functiontooltipwidget.cpp b/RedPandaIDE/widgets/functiontooltipwidget.cpp
index bca2aa22..5f82d48e 100644
--- a/RedPandaIDE/widgets/functiontooltipwidget.cpp
+++ b/RedPandaIDE/widgets/functiontooltipwidget.cpp
@@ -19,6 +19,7 @@
 #include <QHBoxLayout>
 #include <QPushButton>
 #include <QDebug>
+#include <qt_utils/utils.h>
 
 FunctionTooltipWidget::FunctionTooltipWidget(QWidget *parent) :
     QFrame{parent, Qt::ToolTip | Qt::WindowStaysOnTopHint | Qt::WindowDoesNotAcceptFocus},
diff --git a/RedPandaIDE/widgets/labelwithmenu.cpp b/RedPandaIDE/widgets/labelwithmenu.cpp
index 60ceedee..3b0e4108 100644
--- a/RedPandaIDE/widgets/labelwithmenu.cpp
+++ b/RedPandaIDE/widgets/labelwithmenu.cpp
@@ -33,7 +33,11 @@ void LabelWithMenu::mousePressEvent(QMouseEvent *event)
     event->accept();
 }
 
+#if QT_VERSION_MAJOR >= 6
+void LabelWithMenu::enterEvent(QEnterEvent *event)
+#else
 void LabelWithMenu::enterEvent(QEvent *event)
+#endif
 {
     mCursor = cursor();
     setCursor(Qt::PointingHandCursor);
diff --git a/RedPandaIDE/widgets/labelwithmenu.h b/RedPandaIDE/widgets/labelwithmenu.h
index 6e00cfc8..ac6c1171 100644
--- a/RedPandaIDE/widgets/labelwithmenu.h
+++ b/RedPandaIDE/widgets/labelwithmenu.h
@@ -31,7 +31,11 @@ protected:
 
     // QWidget interface
 protected:
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    void enterEvent(QEnterEvent *event) override;
+#else
     void enterEvent(QEvent *event) override;
+#endif
     void leaveEvent(QEvent *event) override;
 
 private:
diff --git a/RedPandaIDE/widgets/qconsole.h b/RedPandaIDE/widgets/qconsole.h
index 1ffd0fc8..c68211ad 100644
--- a/RedPandaIDE/widgets/qconsole.h
+++ b/RedPandaIDE/widgets/qconsole.h
@@ -51,6 +51,9 @@ struct RowColumn {
 struct LineChar {
     int ch;
     int line;
+
+    LineChar() = default;
+    constexpr LineChar(qsizetype ch_, qsizetype line_) : ch(ch_), line(line_) {}
 };
 
 class QConsole;
diff --git a/RedPandaIDE/widgets/qpatchedcombobox.h b/RedPandaIDE/widgets/qpatchedcombobox.h
index ff1227a5..0aed0955 100644
--- a/RedPandaIDE/widgets/qpatchedcombobox.h
+++ b/RedPandaIDE/widgets/qpatchedcombobox.h
@@ -35,6 +35,13 @@ protected:
         QListView::resizeEvent(event);
     }
 
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+    void initViewItemOption(QStyleOptionViewItem *option) const override
+    {
+        QListView::initViewItemOption(option);
+        option->showDecorationSelected = true;
+    }
+#else
     QStyleOptionViewItem viewOptions() const override
     {
         QStyleOptionViewItem option = QListView::viewOptions();
@@ -43,6 +50,7 @@ protected:
 //            option.font = combo->font();
         return option;
     }
+#endif
 
     void paintEvent(QPaintEvent *e) override
     {
@@ -59,7 +67,11 @@ protected:
                 menuOpt.checkType = QStyleOptionMenuItem::NotCheckable;
                 menuOpt.menuRect = e->rect();
                 menuOpt.maxIconWidth = 0;
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+                menuOpt.reservedShortcutWidth = 0;
+#else
                 menuOpt.tabWidth = 0;
+#endif
                 QPainter p(viewport());
                 combo->style()->drawControl(QStyle::CE_MenuEmptyArea, &menuOpt, &p, this);
             }
diff --git a/docs/detailed-build-xdg-cn.md b/docs/detailed-build-xdg-cn.md
index d0322644..291c29e6 100644
--- a/docs/detailed-build-xdg-cn.md
+++ b/docs/detailed-build-xdg-cn.md
@@ -3,7 +3,7 @@
 ## 传统 Unix 方式（`./configure`–`make`–`make install`）
 
 - 安装支持 C++17 的 GCC（≥ 7）或 Clang（≥ 6）。
-- 安装 Qt 5.15 Base、SVG、Tools 模块，包括库和开发文件。
+- 安装 Qt 5.15 或 6.7+ Base、SVG、Tools 模块，包括库和开发文件。
 - 如果使用静态版本的 Qt 编译，还要安装 fcitx5-qt。
 - 安装 astyle 以便在小熊猫 C++ 中对代码进行重新排版。
 
diff --git a/docs/detailed-build-xdg.md b/docs/detailed-build-xdg.md
index 3d88c37f..84796c1d 100644
--- a/docs/detailed-build-xdg.md
+++ b/docs/detailed-build-xdg.md
@@ -3,7 +3,7 @@
 ## Traditional Unix Way (`./configure`–`make`–`make install`)
 
 - Install recent version of GCC (≥ 7) or Clang (≥ 6) that supports C++17.
-- Install Qt 5.15 Base, SVG and Tools modules, including both libraries and development files.
+- Install Qt 5.15 or 6.7+ Base, SVG and Tools modules, including both libraries and development files.
 - Optionally install fcitx5-qt for building with static Qt library.
 - Install astyle for code formatting in Red Panda C++.
 
diff --git a/libs/qsynedit/qsynedit/document.cpp b/libs/qsynedit/qsynedit/document.cpp
index f8e7f5b9..a368524d 100644
--- a/libs/qsynedit/qsynedit/document.cpp
+++ b/libs/qsynedit/qsynedit/document.cpp
@@ -18,12 +18,12 @@
 #include "qt_utils/utils.h"
 #include <QDataStream>
 #include <QFile>
-#include <QTextCodec>
 #include <QTextStream>
 #include <QMutexLocker>
 #include <stdexcept>
 #include <QMessageBox>
 #include <cmath>
+#include <optional>
 #include "qt_utils/charsetinfo.h"
 #include <QDateTime>
 #include <QDebug>
@@ -498,12 +498,11 @@ void Document::insertLines(int index, int numLines)
 
 
 bool Document::tryLoadFileByEncoding(QByteArray encodingName, QFile& file) {
-    QTextCodec* codec = QTextCodec::codecForName(encodingName);
-    if (!codec)
+    TextDecoder decoder(encodingName);
+    if (!decoder.isValid())
         return false;
     file.reset();
     internalClear();
-    QTextCodec::ConverterState state;
     while (true) {
         if (file.atEnd()){
             break;
@@ -516,10 +515,9 @@ bool Document::tryLoadFileByEncoding(QByteArray encodingName, QFile& file) {
         } else if (line.endsWith("\n")){
             line.remove(line.length()-1,1);
         }
-        QString newLine = codec->toUnicode(line.constData(),line.length(),&state);
-        if (state.invalidChars>0) {
+        auto [ok, newLine] = decoder.decode(line);
+        if (!ok) {
             return false;
-            break;
         }
         addItem(newLine);
     }
@@ -528,46 +526,46 @@ bool Document::tryLoadFileByEncoding(QByteArray encodingName, QFile& file) {
 
 void Document::loadUTF16BOMFile(QFile &file)
 {
-    QTextCodec* codec=QTextCodec::codecForName(ENCODING_UTF16);
-    if (!codec)
+    TextDecoder decoder = TextDecoder::decoderForUtf16();
+    if (!decoder.isValid())
         return;
     file.reset();
     internalClear();
     QByteArray buf = file.readAll();
     if (buf.length()<2)
         return;
-    QString text = codec->toUnicode(buf.mid(2));
+    QString text = decoder.decodeUnchecked(buf.mid(2));
     this->setText(text);
 }
 
 void Document::loadUTF32BOMFile(QFile &file)
 {
-    QTextCodec* codec=QTextCodec::codecForName(ENCODING_UTF32);
-    if (!codec)
+    TextDecoder decoder = TextDecoder::decoderForUtf32();
+    if (!decoder.isValid())
         return;
     file.reset();
     internalClear();
     QByteArray buf = file.readAll();
     if (buf.length()<4)
         return;
-    QString text = codec->toUnicode(buf.mid(4));
+    QString text = decoder.decodeUnchecked(buf.mid(4));
     this->setText(text);
 }
 
-void Document::saveUTF16File(QFile &file, QTextCodec* codec)
+void Document::saveUTF16File(QFile &file, TextEncoder &encoder)
 {
-    if (!codec)
+    if (!encoder.isValid())
         return;
     QString text=getTextStr();
-    file.write(codec->fromUnicode(text));
+    file.write(encoder.encodeUnchecked(text));
 }
 
-void Document::saveUTF32File(QFile &file, QTextCodec* codec)
+void Document::saveUTF32File(QFile &file, TextEncoder &encoder)
 {
-    if (!codec)
+    if (!encoder.isValid())
         return;
     QString text=getTextStr();
-    file.write(codec->fromUnicode(text));
+    file.write(encoder.encodeUnchecked(text));
 }
 
 void Document::setTabSize(int newTabSize)
@@ -606,15 +604,14 @@ void Document::loadFromFile(const QString& filename, const QByteArray& encoding,
             return;
         }
         QByteArray line = file.readLine();
-        QTextCodec* codec;
-        QTextCodec::ConverterState state;
+        std::optional<TextDecoder> decoder;
         bool needReread = false;
         bool allAscii = true;
         //test for BOM
         if ((line.length()>=3) && ((unsigned char)line[0]==0xEF) && ((unsigned char)line[1]==0xBB) && ((unsigned char)line[2]==0xBF) ) {
             realEncoding = ENCODING_UTF8_BOM;
             line = line.mid(3);
-            codec = QTextCodec::codecForName(ENCODING_UTF8);
+            decoder = TextDecoder::decoderForUtf8();
         } else if ((line.length()>=4) && ((unsigned char)line[0]==0xFF) && ((unsigned char)line[1]==0xFE)
                    && ((unsigned char)line[2]==0x00)
                    && ((unsigned char)line[3]==0x00)) {
@@ -627,9 +624,9 @@ void Document::loadFromFile(const QString& filename, const QByteArray& encoding,
             return;
         } else {
             realEncoding = ENCODING_UTF8;
-            codec = QTextCodec::codecForName(ENCODING_UTF8);
+            decoder = TextDecoder::decoderForUtf8();
         }
-        if (!codec)
+        if (!decoder.has_value())
             throw FileError(tr("Can't load codec '%1'!").arg(QString(realEncoding)));
         if (line.endsWith("\r\n")) {
             mNewlineType = NewlineType::Windows;
@@ -656,8 +653,8 @@ void Document::loadFromFile(const QString& filename, const QByteArray& encoding,
             if (allAscii) {
                 addItem(QString::fromLatin1(line));
             } else {
-                QString newLine = codec->toUnicode(line.constData(),line.length(),&state);
-                if (state.invalidChars>0) {
+                auto [ok, newLine] = decoder->decode(line);
+                if (!ok) {
                     needReread = true;
                     break;
                 }
@@ -703,13 +700,16 @@ void Document::loadFromFile(const QString& filename, const QByteArray& encoding,
         realEncoding = pCharsetInfoManager->getDefaultSystemEncoding();
     }
     file.reset();
-    QTextStream textStream(&file);
+    QByteArray data = file.readAll();
+    QString text;
+    QTextStream textStream(&text);
     if (realEncoding == ENCODING_UTF8_BOM) {
         textStream.setAutoDetectUnicode(true);
-        textStream.setCodec(ENCODING_UTF8);
+        text = QString::fromUtf8(data);
     } else {
         textStream.setAutoDetectUnicode(false);
-        textStream.setCodec(realEncoding);
+        TextDecoder decoder(realEncoding);
+        text = decoder.decodeUnchecked(data);
     }
     QString line;
     internalClear();
@@ -731,28 +731,28 @@ void Document::saveToFile(QFile &file, const QByteArray& encoding,
                                    const QByteArray& defaultEncoding, QByteArray& realEncoding)
 {
     QMutexLocker locker(&mMutex);
-    QTextCodec* codec;
+    std::optional<TextEncoder> encoder;
     realEncoding = encoding;
     QString codecName = realEncoding;
     if (realEncoding == ENCODING_UTF16_BOM || realEncoding == ENCODING_UTF16) {
-        codec = QTextCodec::codecForName(ENCODING_UTF16);
+        encoder = TextEncoder::encoderForUtf16();
         codecName = ENCODING_UTF16;
     } else if (realEncoding == ENCODING_UTF32_BOM || realEncoding == ENCODING_UTF32) {
-        codec = QTextCodec::codecForName(ENCODING_UTF32);
+        encoder = TextEncoder::encoderForUtf32();
         codecName = ENCODING_UTF32;
     } else if (realEncoding == ENCODING_UTF8_BOM) {
-        codec = QTextCodec::codecForName(ENCODING_UTF8);
+        encoder = TextEncoder::encoderForUtf8();
         codecName = ENCODING_UTF8;
     } else if (realEncoding == ENCODING_SYSTEM_DEFAULT) {
-        codec = QTextCodec::codecForLocale();
+        encoder = TextEncoder::encoderForSystem();
         codecName = realEncoding;
     } else if (realEncoding == ENCODING_AUTO_DETECT) {
-        codec = QTextCodec::codecForName(defaultEncoding);
+        encoder = TextEncoder(defaultEncoding);
         codecName = defaultEncoding;
     } else {
-        codec = QTextCodec::codecForName(realEncoding);
+        encoder = TextEncoder(realEncoding);
     }
-    if (!codec)
+    if (!encoder.has_value() || !encoder->isValid())
         throw FileError(tr("Can't load codec '%1'!").arg(codecName));
 
     if (!file.open(QFile::WriteOnly | QFile::Truncate))
@@ -760,10 +760,10 @@ void Document::saveToFile(QFile &file, const QByteArray& encoding,
     if (mLines.isEmpty())
         return;
     if (realEncoding == ENCODING_UTF16) {
-        saveUTF16File(file,codec);
+        saveUTF16File(file, encoder.value());
         return;
     } else if (realEncoding == ENCODING_UTF32) {
-        saveUTF32File(file,codec);
+        saveUTF32File(file, encoder.value());
         return;
     } if (realEncoding == ENCODING_UTF8_BOM) {
         file.putChar(0xEF);
@@ -774,7 +774,7 @@ void Document::saveToFile(QFile &file, const QByteArray& encoding,
     QByteArray data;
     for (PDocumentLine& line:mLines) {
         QString text = line->lineText()+lineBreak();
-        data = codec->fromUnicode(text);
+        data = encoder->encodeUnchecked(text);
         if (allAscii) {
             allAscii = (data==text.toLatin1());
         }
@@ -784,10 +784,10 @@ void Document::saveToFile(QFile &file, const QByteArray& encoding,
     if (allAscii) {
         realEncoding = ENCODING_ASCII;
     } else if (realEncoding == ENCODING_SYSTEM_DEFAULT) {
-        if (QString(codec->name()).compare("System",Qt::CaseInsensitive)==0) {
+        if (encoder->name().compare("System",Qt::CaseInsensitive)==0) {
             realEncoding = pCharsetInfoManager->getDefaultSystemEncoding();
         } else {
-            realEncoding = codec->name();
+            realEncoding = encoder->name();
         }
     }
 }
diff --git a/libs/qsynedit/qsynedit/document.h b/libs/qsynedit/qsynedit/document.h
index cb4ae6df..293a02d8 100644
--- a/libs/qsynedit/qsynedit/document.h
+++ b/libs/qsynedit/qsynedit/document.h
@@ -647,8 +647,8 @@ private:
     bool tryLoadFileByEncoding(QByteArray encodingName, QFile& file);
     void loadUTF16BOMFile(QFile& file);
     void loadUTF32BOMFile(QFile& file);
-    void saveUTF16File(QFile& file, QTextCodec* codec);
-    void saveUTF32File(QFile& file, QTextCodec* codec);
+    void saveUTF16File(QFile& file, TextEncoder &encoder);
+    void saveUTF32File(QFile& file, TextEncoder &encoder);
 
 private:
     DocumentLines mLines;
diff --git a/libs/qsynedit/qsynedit/exporter/exporter.cpp b/libs/qsynedit/qsynedit/exporter/exporter.cpp
index e98b9ff3..cda8de75 100644
--- a/libs/qsynedit/qsynedit/exporter/exporter.cpp
+++ b/libs/qsynedit/qsynedit/exporter/exporter.cpp
@@ -21,7 +21,7 @@
 #include <QGuiApplication>
 #include <QMimeData>
 #include <QPalette>
-#include <QTextCodec>
+#include <qt_utils/utils.h>
 
 namespace QSynedit {
 
@@ -131,8 +131,9 @@ void Exporter::saveToFile(const QString &filename)
 
 void Exporter::writeToStream(QIODevice &stream)
 {
-    QTextCodec *codec=getCodec();
-    if (stream.write(codec->fromUnicode(mText))<0) {
+    TextEncoder encoder = getEncoder();
+    auto [ok, encoded] = encoder.encode(mText);
+    if (ok && stream.write(encoded) < 0) {
         throw FileError(QObject::tr("Failed to write data."));
     }
 }
@@ -274,12 +275,14 @@ int Exporter::getBufferSize() const
     return mText.size();
 }
 
-QTextCodec * Exporter::getCodec() const {
-    QTextCodec* codec = QTextCodec::codecForName(mCharset);
-    if (codec == nullptr)
-        codec = QTextCodec::codecForLocale();
-    return codec;
+TextEncoder Exporter::getEncoder() const {
+    TextEncoder encoder(mCharset);
+    if (encoder.isValid())
+        return encoder;
+    else
+        return TextEncoder::encoderForSystem();
 }
+
 void Exporter::insertData(int pos, const QString &text)
 {
     if (!text.isEmpty()) {
@@ -339,8 +342,9 @@ void Exporter::setTokenAttribute(PTokenAttribute attri)
 
 QByteArray Exporter::buffer() const
 {
-    QTextCodec* codec = getCodec();
-    return codec->fromUnicode(mText);
+    TextEncoder encoder = getEncoder();
+    auto [_, encoded] = encoder.encode(mText);
+    return encoded;
 }
 
 const QString &Exporter::text() const
diff --git a/libs/qsynedit/qsynedit/exporter/exporter.h b/libs/qsynedit/qsynedit/exporter/exporter.h
index 69281ca2..5197c8d9 100644
--- a/libs/qsynedit/qsynedit/exporter/exporter.h
+++ b/libs/qsynedit/qsynedit/exporter/exporter.h
@@ -242,7 +242,7 @@ protected:
      */
     virtual void setTokenAttribute(PTokenAttribute attri);
 
-    QTextCodec *getCodec() const;
+    TextEncoder getEncoder() const;
 private:
     QString mText;
     bool mFirstAttribute;
diff --git a/libs/qsynedit/qsynedit/gutter.cpp b/libs/qsynedit/qsynedit/gutter.cpp
index 9cf5d055..9ffdcd51 100644
--- a/libs/qsynedit/qsynedit/gutter.cpp
+++ b/libs/qsynedit/qsynedit/gutter.cpp
@@ -16,6 +16,7 @@
  */
 #include "gutter.h"
 #include "algorithm"
+#include <qt_utils/utils.h>
 
 namespace QSynedit {
 
diff --git a/libs/qsynedit/qsynedit/keystrokes.cpp b/libs/qsynedit/qsynedit/keystrokes.cpp
index d8de1e6a..ed3d9989 100644
--- a/libs/qsynedit/qsynedit/keystrokes.cpp
+++ b/libs/qsynedit/qsynedit/keystrokes.cpp
@@ -30,9 +30,9 @@ EditKeyStroke::EditKeyStroke()
 QKeySequence EditKeyStroke::keySequence() const
 {
     if (mKey2 == 0) {
-        return QKeySequence(mKey + mKeyModifiers);
+        return QKeySequence(mKey | mKeyModifiers);
     } else {
-        return QKeySequence(mKey + mKeyModifiers, mKey2+mKeyModifiers2);
+        return QKeySequence(mKey | mKeyModifiers, mKey2 | mKeyModifiers2);
     }
 }
 
diff --git a/libs/qsynedit/qsynedit/syntaxer/asm.cpp b/libs/qsynedit/qsynedit/syntaxer/asm.cpp
index deee944d..062c7b2b 100644
--- a/libs/qsynedit/qsynedit/syntaxer/asm.cpp
+++ b/libs/qsynedit/qsynedit/syntaxer/asm.cpp
@@ -309,7 +309,7 @@ void ASMSyntaxer::SpaceProc()
         mRun++;
         if (mLine[mRun] == 0 || mLine[mRun] == '\r' || mLine[mRun] == '\n')
             break;
-        if (mLine[mRun] > 32)
+        if (!isLexicalSpace(mLine[mRun]))
             break;
     }
     if (mRun>=mStringLen)
@@ -1696,7 +1696,7 @@ void ASMSyntaxer::next()
             NumberProc();
         } else if (isIdentStartChar(mLine[mRun])) {
             IdentProc(IdentPrefix::None);
-        } else if (mLine[mRun]<=32) {
+        } else if (isLexicalSpace(mLine[mRun])) {
             SpaceProc();
         } else {
             UnknownProc();
diff --git a/libs/qsynedit/qsynedit/syntaxer/cpp.cpp b/libs/qsynedit/qsynedit/syntaxer/cpp.cpp
index bfc12999..bcbb6a2b 100644
--- a/libs/qsynedit/qsynedit/syntaxer/cpp.cpp
+++ b/libs/qsynedit/qsynedit/syntaxer/cpp.cpp
@@ -16,6 +16,7 @@
  */
 #include "cpp.h"
 #include "../constants.h"
+#include "qt_utils/utils.h"
 
 #include <QFont>
 #include <QDebug>
@@ -1069,7 +1070,7 @@ void CppSyntaxer::procSpace()
 {
     mRun += 1;
     mTokenId = TokenId::Space;
-    while (mRun<mLineSize && mLine[mRun]>=1 && mLine[mRun]<=32)
+    while (mRun < mLineSize && isLexicalSpace(mLine[mRun]))
         mRun+=1;
     if (mRun>=mLineSize) {
         mRange.hasTrailingSpaces = true;
diff --git a/libs/qsynedit/qsynedit/syntaxer/glsl.cpp b/libs/qsynedit/qsynedit/syntaxer/glsl.cpp
index 82f388d1..15e01a3e 100644
--- a/libs/qsynedit/qsynedit/syntaxer/glsl.cpp
+++ b/libs/qsynedit/qsynedit/syntaxer/glsl.cpp
@@ -846,7 +846,7 @@ void GLSLSyntaxer::spaceProc()
 {
     mRun += 1;
     mTokenId = TokenId::Space;
-    while (mLine[mRun]>=1 && mLine[mRun]<=32)
+    while (isLexicalSpace(mLine[mRun]))
         mRun+=1;
     mRange.state = RangeState::rsUnknown;
     if (mRun>=mLineSize)
diff --git a/libs/qsynedit/qsynedit/syntaxer/lua.cpp b/libs/qsynedit/qsynedit/syntaxer/lua.cpp
index 53fa7827..819ab98e 100644
--- a/libs/qsynedit/qsynedit/syntaxer/lua.cpp
+++ b/libs/qsynedit/qsynedit/syntaxer/lua.cpp
@@ -16,6 +16,7 @@
  */
 #include "lua.h"
 #include "../constants.h"
+#include "qt_utils/utils.h"
 
 #include <QFont>
 #include <QDebug>
@@ -587,7 +588,7 @@ void LuaSyntaxer::spaceProc()
 {
     mRun += 1;
     mTokenId = TokenId::Space;
-    while (mRun<mLineSize && mLine[mRun]>=1 && mLine[mRun]<=32)
+    while (mRun<mLineSize && isLexicalSpace(mLine[mRun]))
         mRun+=1;
     if (mRun>=mLineSize) {
         mRange.hasTrailingSpaces = true;
diff --git a/libs/qsynedit/qsynedit/syntaxer/makefile.cpp b/libs/qsynedit/qsynedit/syntaxer/makefile.cpp
index 1980c7d6..81542506 100644
--- a/libs/qsynedit/qsynedit/syntaxer/makefile.cpp
+++ b/libs/qsynedit/qsynedit/syntaxer/makefile.cpp
@@ -200,7 +200,7 @@ MakefileSyntaxer::MakefileSyntaxer()
 void MakefileSyntaxer::procSpace()
 {
     mTokenID = TokenId::Space;
-    while (mLine[mRun]!=0 && mLine[mRun]<=32)
+    while (mLine[mRun]!=0 && mLine[mRun] <= ' ')
         mRun++;
     if (mRun>=mStringLen)
         mHasTrailingSpaces = true;
diff --git a/libs/qsynedit/qsynedit/types.h b/libs/qsynedit/qsynedit/types.h
index c4047407..346883ee 100644
--- a/libs/qsynedit/qsynedit/types.h
+++ b/libs/qsynedit/qsynedit/types.h
@@ -46,6 +46,10 @@ enum class ProgrammingLanguage {
 struct BufferCoord {
     int ch;
     int line;
+
+    BufferCoord() = default;
+    constexpr BufferCoord(qsizetype ch_, qsizetype line_) : ch(ch_), line(line_) {}
+
     bool operator==(const BufferCoord& coord);
     bool operator>=(const BufferCoord& coord);
     bool operator>(const BufferCoord& coord);
diff --git a/libs/redpanda_qt_utils/qt_utils/charsetinfo.cpp b/libs/redpanda_qt_utils/qt_utils/charsetinfo.cpp
index ce37f57d..a0e0edb2 100644
--- a/libs/redpanda_qt_utils/qt_utils/charsetinfo.cpp
+++ b/libs/redpanda_qt_utils/qt_utils/charsetinfo.cpp
@@ -21,8 +21,6 @@
 #include <QSet>
 #ifdef Q_OS_WIN
 #include <windows.h>
-#else
-#include <langinfo.h>
 #endif
 
 CharsetInfoManager* pCharsetInfoManager;
@@ -37,7 +35,7 @@ QByteArray CharsetInfoManager::getDefaultSystemEncoding()
     }
     return "unknown";
 #else
-    return QByteArray(nl_langinfo(CODESET));
+    return "UTF-8";
 #endif
 }
 
diff --git a/libs/redpanda_qt_utils/qt_utils/utils.cpp b/libs/redpanda_qt_utils/qt_utils/utils.cpp
index 84c63e4b..6dd464da 100644
--- a/libs/redpanda_qt_utils/qt_utils/utils.cpp
+++ b/libs/redpanda_qt_utils/qt_utils/utils.cpp
@@ -23,7 +23,6 @@
 #include <QProcess>
 #include <QProcessEnvironment>
 #include <QString>
-#include <QTextCodec>
 #include <QtGlobal>
 #include <QDebug>
 #include <QStyleFactory>
@@ -33,6 +32,8 @@
 #include <QScreen>
 #include <QDirIterator>
 #include <QTextEdit>
+#include "charsetinfo.h"
+
 #ifdef Q_OS_WIN
 #include <QDirIterator>
 #include <QFont>
@@ -40,7 +41,12 @@
 #include <QMimeDatabase>
 #include <windows.h>
 #endif
-#include "charsetinfo.h"
+
+#if QT_VERSION_MAJOR >= 6
+# include <QStringConverter>
+#else
+# include <QTextCodec>
+#endif
 
 BaseError::BaseError(const QString &reason):
 mReason(reason)
@@ -64,7 +70,7 @@ FileError::FileError(const QString &reason): BaseError(reason)
 
 }
 
-const QByteArray guessTextEncoding(const QByteArray& text){
+QString guessTextEncoding(const QByteArray& text){
     bool allAscii;
     int ii;
     int size;
@@ -253,14 +259,16 @@ QByteArray toByteArray(const QString &s)
 
 QString fromByteArray(const QByteArray &s)
 {
-    QTextCodec* codec = QTextCodec::codecForName(ENCODING_UTF8);
-    QTextCodec::ConverterState state;
-    if (!codec)
-        return QString(s);
-    QString tmp = codec->toUnicode(s,s.length(),&state);
-    if (state.invalidChars>0)
-        tmp = QString::fromLocal8Bit(s);
-    return tmp;
+#ifdef Q_OS_WIN
+    TextDecoder decoder = TextDecoder::decoderForUtf8();
+    auto [ok, result] = decoder.decode(s);
+    if (ok)
+        return result;
+    else
+        return QString::fromLocal8Bit(s);
+#else
+    return QString::fromUtf8(s);
+#endif
 }
 
 QStringList readStreamToLines(QTextStream *stream)
@@ -282,37 +290,13 @@ void readStreamToLines(QTextStream *stream,
     }
 }
 
-QStringList readFileToLines(const QString& fileName, QTextCodec* codec)
-{
-    QFile file(fileName);
-    if (file.open(QFile::ReadOnly)) {
-        QTextStream stream(&file);
-        stream.setCodec(codec);
-        stream.setAutoDetectUnicode(false);
-        return readStreamToLines(&stream);
-    }
-    return QStringList();
-}
-
-void readFileToLines(const QString &fileName, QTextCodec *codec, LineProcessFunc lineFunc)
-{
-    QFile file(fileName);
-    if (file.open(QFile::ReadOnly)) {
-        QTextStream stream(&file);
-        stream.setCodec(codec);
-        stream.setAutoDetectUnicode(false);
-        readStreamToLines(&stream, lineFunc);
-    }
-}
-
 static QStringList tryLoadFileByEncoding(QByteArray encodingName, QFile& file, bool* isOk) {
     QStringList result;
-    *isOk=false;
-    QTextCodec* codec = QTextCodec::codecForName(encodingName);
-    if (!codec)
+    *isOk = false;
+    TextDecoder decoder(encodingName);
+    if (!decoder.isValid())
         return result;
     file.reset();
-    QTextCodec::ConverterState state;
     while (true) {
         if (file.atEnd()){
             break;
@@ -325,8 +309,8 @@ static QStringList tryLoadFileByEncoding(QByteArray encodingName, QFile& file, b
         } else if (line.endsWith("\n")){
             line.remove(line.length()-1,1);
         }
-        QString newLine = codec->toUnicode(line.constData(),line.length(),&state);
-        if (state.invalidChars>0) {
+        auto [ok, newLine] = decoder.decode(line);
+        if (!ok) {
             return QStringList();
         }
         result.append(newLine);
@@ -355,12 +339,12 @@ QStringList readFileToLines(const QString &fileName)
         }
         QList<PCharsetInfo> charsets = pCharsetInfoManager->findCharsetByLocale(pCharsetInfoManager->localeName());
         if (!charsets.isEmpty()) {
-            QSet<QByteArray> encodingSet;
+            QSet<QString> encodingSet;
             for (int i=0;i<charsets.size();i++) {
                 encodingSet.insert(charsets[i]->name);
             }
             encodingSet.remove(realEncoding);
-            foreach (const QByteArray& encodingName,encodingSet) {
+            foreach (const QString& encodingName,encodingSet) {
                 if (encodingName == ENCODING_UTF8)
                     continue;
                 result = tryLoadFileByEncoding("UTF-8",file,&ok);
@@ -765,3 +749,273 @@ const QChar *getNullTerminatedStringData(const QString &str)
     }
     return result;
 }
+
+TextEncoder::TextEncoder(const char *name)
+{
+#if QT_VERSION_MAJOR >= 6
+    mEncoder = QStringEncoder(name, QStringConverter::Flag::Stateless);
+#else
+    mCodec = QTextCodec::codecForName(name);
+#endif
+}
+
+TextEncoder::TextEncoder(const QByteArray &name) :
+    TextEncoder(name.data())
+{
+}
+
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+TextEncoder::TextEncoder(QStringEncoder &&encoder)
+{
+    mEncoder = std::move(encoder);
+}
+#endif
+
+bool TextEncoder::isValid() const
+{
+#if QT_VERSION_MAJOR >= 6
+    return mEncoder.isValid();
+#else
+    return mCodec != nullptr;
+#endif
+}
+
+QByteArray TextEncoder::name() const
+{
+#if QT_VERSION_MAJOR >= 6
+    return mEncoder.name();
+#else
+    return mCodec->name();
+#endif
+}
+
+std::pair<bool, QByteArray> TextEncoder::encode(const QString &text)
+{
+    if (!isValid())
+        return {false, QByteArray()};
+    QByteArray result;
+#if QT_VERSION_MAJOR >= 6
+    result = mEncoder(text);
+    if (mEncoder.hasError()) {
+        mEncoder.resetState();
+        return {false, QByteArray()};
+    }
+#else
+    QTextCodec::ConverterState state;
+    result = mCodec->fromUnicode(text.constData(), text.length(), &state);
+    if (state.invalidChars > 0)
+        return {false, QByteArray()};
+#endif
+    return {true, result};
+}
+
+QByteArray TextEncoder::encodeUnchecked(const QString &text)
+{
+    if (!isValid())
+        return QByteArray();
+#if QT_VERSION_MAJOR >= 6
+    QByteArray result = mEncoder(text);
+    if (mEncoder.hasError())
+        mEncoder.resetState();
+    return result;
+#else
+    return mCodec->fromUnicode(text);
+#endif
+}
+
+TextEncoder TextEncoder::encoderForUtf8()
+{
+#if QT_VERSION_MAJOR >= 6
+    return QStringEncoder(QStringConverter::Utf8, QStringConverter::Flag::Stateless);
+#else
+    return TextEncoder(ENCODING_UTF8);
+#endif
+}
+
+TextEncoder TextEncoder::encoderForUtf16()
+{
+#if QT_VERSION_MAJOR >= 6
+    return QStringEncoder(QStringConverter::Utf16, QStringConverter::Flag::Stateless);
+#else
+    return TextEncoder(ENCODING_UTF16);
+#endif
+}
+
+TextEncoder TextEncoder::encoderForUtf32()
+{
+#if QT_VERSION_MAJOR >= 6
+    return QStringEncoder(QStringConverter::Utf32, QStringConverter::Flag::Stateless);
+#else
+    return TextEncoder(ENCODING_UTF32);
+#endif
+}
+
+TextEncoder TextEncoder::encoderForSystem()
+{
+#ifdef Q_OS_WIN
+# if QT_VERSION_MAJOR >= 6
+    return QStringEncoder(QStringConverter::System, QStringConverter::Flag::Stateless);
+# else
+    return TextEncoder(ENCODING_SYSTEM_DEFAULT);
+# endif
+#else
+    return encoderForUtf8();
+#endif
+}
+
+TextDecoder::TextDecoder(const char *name)
+{
+#if QT_VERSION_MAJOR >= 6
+    mDecoder = QStringDecoder(name, QStringConverter::Flag::Stateless);
+#else
+    mCodec = QTextCodec::codecForName(name);
+#endif
+}
+
+TextDecoder::TextDecoder(const QByteArray &name) :
+    TextDecoder(name.data())
+{
+}
+
+#if QT_VERSION_MAJOR >= 6
+TextDecoder::TextDecoder(QStringDecoder &&decoder)
+{
+    mDecoder = std::move(decoder);
+}
+#endif
+
+bool TextDecoder::isValid() const
+{
+#if QT_VERSION_MAJOR >= 6
+    return mDecoder.isValid();
+#else
+    return mCodec != nullptr;
+#endif
+}
+
+QByteArray TextDecoder::name() const
+{
+#if QT_VERSION_MAJOR >= 6
+    return mDecoder.name();
+#else
+    return mCodec->name();
+#endif
+}
+
+std::pair<bool, QString> TextDecoder::decode(const QByteArray &text)
+{
+    if (!isValid())
+        return {false, QString()};
+    QString result;
+#if QT_VERSION_MAJOR >= 6
+    result = mDecoder(text);
+    if (mDecoder.hasError()) {
+        mDecoder.resetState();
+        return {false, QString()};
+    }
+#else
+    QTextCodec::ConverterState state;
+    result = mCodec->toUnicode(text.constData(), text.length(), &state);
+    if (state.invalidChars > 0)
+        return {false, QString()};
+#endif
+    return {true, result};
+}
+
+QString TextDecoder::decodeUnchecked(const QByteArray &text)
+{
+    if (!isValid())
+        return QString();
+#if QT_VERSION_MAJOR >= 6
+    QString result = mDecoder(text);
+    if (mDecoder.hasError())
+        mDecoder.resetState();
+    return result;
+#else
+    return mCodec->toUnicode(text);
+#endif
+}
+
+TextDecoder TextDecoder::decoderForUtf8()
+{
+#if QT_VERSION_MAJOR >= 6
+    return QStringDecoder(QStringConverter::Utf8, QStringConverter::Flag::Stateless);
+#else
+    return TextDecoder(ENCODING_UTF8);
+#endif
+}
+
+TextDecoder TextDecoder::decoderForUtf16()
+{
+#if QT_VERSION_MAJOR >= 6
+    return QStringDecoder(QStringConverter::Utf16, QStringConverter::Flag::Stateless);
+#else
+    return TextDecoder(ENCODING_UTF16);
+#endif
+}
+
+TextDecoder TextDecoder::decoderForUtf32()
+{
+#if QT_VERSION_MAJOR >= 6
+    return QStringDecoder(QStringConverter::Utf32, QStringConverter::Flag::Stateless);
+#else
+    return TextDecoder(ENCODING_UTF32);
+#endif
+}
+
+TextDecoder TextDecoder::decoderForSystem()
+{
+#ifdef Q_OS_WIN
+# if QT_VERSION_MAJOR >= 6
+    return QStringDecoder(QStringConverter::System, QStringConverter::Flag::Stateless);
+# else
+    return TextDecoder(ENCODING_SYSTEM_DEFAULT);
+# endif
+#else
+    return decoderForUtf8();
+#endif
+}
+
+const QStringList &availableEncodings() {
+    static bool initialized = false;
+    static QStringList encodings;
+
+    if (initialized)
+        return encodings;
+
+#if QT_VERSION_MAJOR >= 6
+    for (const QString &name : QStringConverter::availableCodecs()) {
+        QString lname = name.toLower();
+        if (lname.startsWith("cp"))
+            continue;
+        if (lname == "locale" || lname == "utf-8")
+            continue;
+        encodings.append(name);
+    }
+#else
+    QSet<QByteArray> codecAlias = {"system", "utf-8"};
+    for (const QByteArray &name : QTextCodec::availableCodecs()) {
+        QByteArray lname = name.toLower();
+        if (lname.startsWith("cp"))
+            continue;
+        if (codecAlias.contains(lname))
+            continue;
+        encodings.append(name);
+        codecAlias.insert(lname);
+        QTextCodec *codec = QTextCodec::codecForName(name);
+        if (codec != nullptr) {
+            for (const QByteArray &alias : codec->aliases())
+                codecAlias.insert(alias.toLower());
+        }
+    }
+#endif
+    std::sort(encodings.begin(), encodings.end());
+    initialized = true;
+    return encodings;
+}
+
+bool isEncodingAvailable(const QByteArray &encoding)
+{
+    TextEncoder encoder(encoding);
+    return encoder.isValid();
+}
diff --git a/libs/redpanda_qt_utils/qt_utils/utils.h b/libs/redpanda_qt_utils/qt_utils/utils.h
index cd6dcd36..fa21f981 100644
--- a/libs/redpanda_qt_utils/qt_utils/utils.h
+++ b/libs/redpanda_qt_utils/qt_utils/utils.h
@@ -26,9 +26,15 @@
 #include <QThread>
 #include <QProcessEnvironment>
 
+#if QT_VERSION_MAJOR >= 6
+# include <QStringEncoder>
+# include <QStringDecoder>
+#else
+class QTextCodec;
+#endif
+
 class QByteArray;
 class QTextStream;
-class QTextCodec;
 
 #define ENCODING_AUTO_DETECT "AUTO"
 #define ENCODING_UTF8   "UTF-8"
@@ -67,7 +73,7 @@ public:
 };
 
 /* text processing utils */
-const QByteArray guessTextEncoding(const QByteArray& text);
+QString guessTextEncoding(const QByteArray& text);
 
 const QChar *getNullTerminatedStringData(const QString& str);
 
@@ -109,9 +115,7 @@ void readStreamToLines(QTextStream* stream, LineProcessFunc lineFunc);
  * @param codec
  * @return
  */
-QStringList readFileToLines(const QString& fileName, QTextCodec* codec);
 QStringList readFileToLines(const QString& fileName);
-void readFileToLines(const QString& fileName, QTextCodec* codec, LineProcessFunc lineFunc);
 
 QByteArray readFileToByteArray(const QString& fileName);
 
@@ -204,4 +208,108 @@ finally(F&& f) noexcept
     return final_action<typename std::remove_cv<typename std::remove_reference<F>::type>::type>(
         std::forward<F>(f));
 }
+
+class TextEncoder {
+public:
+    explicit TextEncoder(const char *name);
+    explicit TextEncoder(const QByteArray &name);
+    TextEncoder(const TextEncoder &other) = delete;
+    TextEncoder(TextEncoder &&other) noexcept = default;
+    TextEncoder &operator=(const TextEncoder &other) = delete;
+    TextEncoder &operator=(TextEncoder &&other) noexcept = default;
+    ~TextEncoder() = default;
+
+#if QT_VERSION_MAJOR >= 6
+private:
+    TextEncoder(QStringEncoder &&encoder);
+#endif
+
+public:
+    bool isValid() const;
+    QByteArray name() const;
+    std::pair<bool, QByteArray> encode(const QString &text);
+    QByteArray encodeUnchecked(const QString &text);
+
+public:
+    static TextEncoder encoderForUtf8();
+    static TextEncoder encoderForUtf16();
+    static TextEncoder encoderForUtf32();
+    static TextEncoder encoderForSystem();
+
+private:
+#if QT_VERSION_MAJOR >= 6
+    QStringEncoder mEncoder;
+#else
+    QTextCodec *mCodec;
+#endif
+};
+
+class TextDecoder {
+public:
+    explicit TextDecoder(const char *name);
+    explicit TextDecoder(const QByteArray &name);
+    TextDecoder(const TextDecoder &other) = delete;
+    TextDecoder(TextDecoder &&other) noexcept = default;
+    TextDecoder &operator=(const TextDecoder &other) = delete;
+    TextDecoder &operator=(TextDecoder &&other) noexcept = default;
+    ~TextDecoder() = default;
+
+#if QT_VERSION_MAJOR >= 6
+private:
+    TextDecoder(QStringDecoder &&decoder);
+#endif
+
+public:
+    bool isValid() const;
+    QByteArray name() const;
+    std::pair<bool, QString> decode(const QByteArray &text);
+    QString decodeUnchecked(const QByteArray &text);
+
+public:
+    static TextDecoder decoderForUtf8();
+    static TextDecoder decoderForUtf16();
+    static TextDecoder decoderForUtf32();
+    static TextDecoder decoderForSystem();
+
+private:
+#if QT_VERSION_MAJOR >= 6
+    QStringDecoder mDecoder;
+#else
+    QTextCodec *mCodec;
+#endif
+};
+
+const QStringList &availableEncodings();
+
+bool isEncodingAvailable(const QByteArray &encoding);
+
+#if QT_VERSION_MAJOR >= 6
+
+namespace std {
+    constexpr inline int max(int a, qsizetype b) {
+        return max<int>(a, b);
+    }
+    constexpr inline int max(qsizetype a, int b) {
+        return max<int>(a, b);
+    }
+    constexpr inline int min(int a, qsizetype b) {
+        return min<int>(a, b);
+    }
+    constexpr inline int min(qsizetype a, int b) {
+        return min<int>(a, b);
+    }
+}
+
+#endif
+
+inline bool isAsciiPrint(int c)
+{
+    return c >= 32 && c <= 126;
+}
+
+inline bool isLexicalSpace(QChar c)
+{
+    return c.unicode() >= 1 && c.unicode() <= 32;
+}
+
 #endif // UTILS_H
diff --git a/packages/archlinux/01-in-docker.sh b/packages/archlinux/01-in-docker.sh
index 7c8a6af4..af0d7ff5 100755
--- a/packages/archlinux/01-in-docker.sh
+++ b/packages/archlinux/01-in-docker.sh
@@ -11,7 +11,7 @@ pacman -Syu --noconfirm --needed base-devel git
 
 useradd -m builduser
 echo 'builduser ALL=(ALL) NOPASSWD: ALL' > /etc/sudoers.d/builduser
-echo "MAKEFLAGS=-j$(($(nproc)+1))" >>/etc/makepkg.conf
+echo "MAKEFLAGS=-j$(($(nproc)+1))" >>/etc/makepkg.conf.d/jobs.conf
 
 su builduser -c "git config --global --add safe.directory $PWD"
 su builduser -c ./packages/archlinux/buildpkg.sh
diff --git a/packages/archlinux/PKGBUILD.in b/packages/archlinux/PKGBUILD.in
index 3763d647..8160fb01 100644
--- a/packages/archlinux/PKGBUILD.in
+++ b/packages/archlinux/PKGBUILD.in
@@ -6,8 +6,8 @@ pkgdesc='A fast, lightweight, open source, and cross platform C++ IDE (developme
 arch=('i686' 'pentium4' 'x86_64' 'arm' 'armv6h' 'armv7h' 'aarch64' 'riscv64')
 url="https://github.com/royqh1979/$_pkgname"
 license=('GPL3')
-depends=(qt5-base qt5-svg gcc gdb astyle)
-makedepends=(qt5-tools imagemagick librsvg)
+depends=(qt6-base qt6-svg gcc gdb astyle)
+makedepends=(qt6-tools imagemagick librsvg)
 optdepends=(
     'clang: C/C++ compiler (alternative)'
 )
@@ -29,7 +29,7 @@ prepare() {
 build() {
     mkdir redpanda-build
     cd redpanda-build
-    qmake \
+    qmake6 \
         PREFIX='/usr' \
         LIBEXECDIR='/usr/lib' \
         "$srcdir/$_pkgname/Red_Panda_CPP.pro"