diff --git a/app/app.pri b/app/app.pri
index 545eab4..c5d2340 100644
--- a/app/app.pri
+++ b/app/app.pri
@@ -5,6 +5,7 @@ VERSION = $${APPVERSION}
 LANGUAGE = C++
 CONFIG += qt warn_on thread
 QT += core gui widgets
+greaterThan(QT_MAJOR_VERSION, 5): QT += core5compat
 
 DEFINES += QT_STL QT_NO_CAST_FROM_ASCII QT_NO_CAST_TO_ASCII QT_NO_CAST_FROM_BYTEARRAY QT_STRICT_ITERATORS QT_NO_URL_CAST_FROM_STRING QT_NO_KEYWORDS
 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x050200
diff --git a/app/configeditorwidget.cpp b/app/configeditorwidget.cpp
index db88b22..a8a75c4 100644
--- a/app/configeditorwidget.cpp
+++ b/app/configeditorwidget.cpp
@@ -22,7 +22,7 @@
 #include "configeditorwidget.h"
 
 #include <QtCore/QSettings>
-#include <QTextCodec>
+#include <QtCore5Compat/QTextCodec>
 #include <QtWidgets/QApplication>
 
 #include "../common/utils/fontdialog.h"
diff --git a/app/editreplacecurrentwidget.cpp b/app/editreplacecurrentwidget.cpp
index 3786514..ab76d7d 100644
--- a/app/editreplacecurrentwidget.cpp
+++ b/app/editreplacecurrentwidget.cpp
@@ -43,7 +43,7 @@ ReplaceCurrentWidget::ReplaceCurrentWidget(QWidget *parent) : QWidget(parent)
     buttonsLayout->addWidget(dontReplaceButton);
     buttonsLayout->addWidget(cancelButton);
     buttonsLayout->addStretch();
-    buttonsLayout->setMargin(0);
+    buttonsLayout->setContentsMargins(0, 0, 0, 0);
     buttonsWidget->setLayout(buttonsLayout);
     mainLayout->addWidget(m_replaceLabel);
     mainLayout->addWidget(buttonsWidget);
diff --git a/app/linenumberwidget.cpp b/app/linenumberwidget.cpp
index 72712ca..1f5037b 100644
--- a/app/linenumberwidget.cpp
+++ b/app/linenumberwidget.cpp
@@ -99,8 +99,8 @@ void LineNumberWidget::paintEvent(QPaintEvent *event)
 void LineNumberWidget::mousePressEvent(QMouseEvent *event)
 {
     event->accept();
-    const QPoint p = m_editor->viewport()->mapFromGlobal(event->globalPos());
-    const int lineNumber = m_editor->cursorForPosition(p).blockNumber() + 1;
+    const QPointF p = m_editor->viewport()->mapFromGlobal(event->globalPosition());
+    const int lineNumber = m_editor->cursorForPosition(p.toPoint()).blockNumber() + 1;
     if (lineNumber <= 0)
         return;
 
diff --git a/app/loghighlighter.cpp b/app/loghighlighter.cpp
index a9b9dc6..e085c54 100644
--- a/app/loghighlighter.cpp
+++ b/app/loghighlighter.cpp
@@ -38,7 +38,7 @@ LogHighlighter::LogHighlighter(QTextDocument *parent) : QSyntaxHighlighter(paren
                                                         // TikzPreviewGenerator::getParsedLogText()
             << tr("This program will not work!");
     for (const auto &pattern : keywordPatterns) {
-        rule.pattern = QRegExp(pattern);
+        rule.pattern = QRegularExpression(pattern);
         rule.format = keywordFormat;
         m_highlightingRules.append(rule);
     }
@@ -46,7 +46,7 @@ LogHighlighter::LogHighlighter(QTextDocument *parent) : QSyntaxHighlighter(paren
     QTextCharFormat commandFormat;
     commandFormat.setForeground(Qt::darkBlue);
     commandFormat.setFontWeight(QFont::Bold);
-    rule.pattern = QRegExp(QLatin1String("^\\[[^\\]\\d][^\\]]*\\]"));
+    rule.pattern = QRegularExpression(QLatin1String("^\\[[^\\]\\d][^\\]]*\\]"));
     rule.format = commandFormat;
     m_highlightingRules.append(rule);
 
@@ -61,15 +61,13 @@ void LogHighlighter::highlightBlock(const QString &text)
 {
     // Try each highlighting pattern and apply formatting if it matches
     for (const auto &rule : m_highlightingRules) {
-        // const QRegExp expression(rule.pattern);
-        // int index = text.indexOf(expression);
-        QRegExp expression(rule.pattern);
-        int index = expression.indexIn(text);
-        while (index >= 0) {
-            const int length = expression.matchedLength();
-            setFormat(index, length, rule.format);
-            // index = text.indexOf(expression, index + length);
-            index = expression.indexIn(text, index + length);
+        QRegularExpression expression(rule.pattern);
+        QRegularExpressionMatch match = expression.match(text);
+        while (match.hasMatch())
+        {
+            const int length = match.capturedLength();
+            setFormat(match.capturedStart(), length, rule.format);
+            match = expression.match(text, match.capturedEnd() + 1);
         }
     }
 
diff --git a/app/loghighlighter.h b/app/loghighlighter.h
index 901767d..5e7981d 100644
--- a/app/loghighlighter.h
+++ b/app/loghighlighter.h
@@ -23,6 +23,7 @@
 
 #include <QtGui/QSyntaxHighlighter>
 #include <QtGui/QTextCharFormat>
+#include <QRegularExpression>
 
 /** A simple, incomplete highlighter for LaTeX .log files
  * @author Florian Hackenberger <florian@hackenberger.at>
@@ -44,7 +45,7 @@ protected:
 private:
     struct LogHighlightingRule
     {
-        QRegExp pattern; /// The pattern to match for formatting
+        QRegularExpression pattern; /// The pattern to match for formatting
         QTextCharFormat format; /// The style of the formatting
     };
     /// All highlighting rules with their formatting for easy iteration
diff --git a/app/mainwindow.cpp b/app/mainwindow.cpp
index e01f254..c4cdb5c 100644
--- a/app/mainwindow.cpp
+++ b/app/mainwindow.cpp
@@ -38,7 +38,7 @@
 #include <QMenuBar>
 #include <QScreen>
 #include <QStatusBar>
-#include <QtCore/QTextCodec>
+#include <QtCore5Compat/QTextCodec>
 #include <QtCore/QProcess>
 #include <QtCore/QSettings>
 #include <QtCore/QTextStream>
@@ -82,7 +82,7 @@
 
 QList<MainWindow *> MainWindow::s_mainWindowList;
 
-MainWindow::MainWindow()
+MainWindow::MainWindow() : m_doOverrideEncoder(false), m_doOverrideDecoder(false)
 {
 // QTime t = QTime::currentTime();
 #ifndef KTIKZ_USE_KDE
@@ -140,7 +140,7 @@ MainWindow::MainWindow()
     QWidget *mainWidget = new QWidget(this);
     QVBoxLayout *mainLayout = new QVBoxLayout(mainWidget);
     mainLayout->setSpacing(0);
-    mainLayout->setMargin(0);
+    mainLayout->setContentsMargins(0, 0, 0, 0);
     mainLayout->addWidget(m_tikzPreviewController->templateWidget());
     mainLayout->addWidget(m_tikzEditorView);
 
@@ -933,12 +933,32 @@ void MainWindow::applySettings()
     updateCompleter();
     settings.beginGroup(QLatin1String("encoding"));
     QVariant qv = settings.value(QLatin1String("default"));
-    setCurrentEncoding(qv.isNull() ? QTextCodec::codecForLocale()
-                                   : QTextCodec::codecForName(qv.toByteArray()));
+    if (qv.isNull())
+    {
+        setCurrentEncoding( QStringConverter::System ) ;
+    } else {
+        std::optional<QStringConverter::Encoding> currentEncoding = QStringConverter::encodingForName(qv.toString().toStdString().c_str());
+        setCurrentEncoding( currentEncoding.value_or( QStringConverter::System ) ) ;
+    }
+
     qv = settings.value(QLatin1String("encoder"));
-    m_overrideEncoder = qv.isNull() ? NULL : QTextCodec::codecForName(qv.toByteArray());
+    if (qv.isNull())
+    {
+        m_doOverrideEncoder = false;
+    } else {
+        std::optional<QStringConverter::Encoding> overrideEncoding = QStringConverter::encodingForName(qv.toString().toStdString().c_str());
+        m_doOverrideEncoder = overrideEncoding.has_value();
+        m_overrideEncoder = overrideEncoding.value_or( QStringConverter::System ) ;
+    }
     qv = settings.value(QLatin1String("decoder"));
-    m_overrideDecoder = qv.isNull() ? NULL : QTextCodec::codecForName(qv.toByteArray());
+    if (qv.isNull())
+    {
+        m_doOverrideDecoder = false;
+    } else {
+        std::optional<QStringConverter::Encoding> overrideDecoding = QStringConverter::encodingForName(qv.toString().toStdString().c_str());
+        m_doOverrideDecoder = overrideDecoding.has_value();
+        m_overrideDecoder = overrideDecoding.value_or( QStringConverter::System ) ;
+    }
     m_encoderBom = settings.value(QLatin1String("bom"), true).toBool();
     settings.endGroup();
 
@@ -1069,7 +1089,7 @@ void MainWindow::loadUrl(const QUrl &url)
         QApplication::setOverrideCursor(Qt::WaitCursor);
         this->configureStreamDecoding(in);
         m_tikzQtEditorView->editor()->setPlainText(in.readAll());
-        setCurrentEncoding(in.codec());
+        setCurrentEncoding(in.encoding());
     }
 
     QApplication::restoreOverrideCursor();
@@ -1131,7 +1151,7 @@ bool MainWindow::saveUrl(const QUrl &url)
     return true;
 }
 
-void MainWindow::setCurrentEncoding(QTextCodec *codec)
+void MainWindow::setCurrentEncoding(QStringConverter::Encoding codec )
 {
     m_currentEncoding = codec;
     // TODO: implement user warning and suggestion to reload the file.
@@ -1160,27 +1180,22 @@ QString MainWindow::strippedName(const QUrl &url) const
     return (fileName.isEmpty()) ? QLatin1String("untitled.txt") : fileName;
 }
 
-QTextCodec *MainWindow::getEncoder() const
+QStringConverter::Encoding MainWindow::getEncoder() const
 {
-    return this->m_overrideEncoder ? this->m_overrideEncoder : this->m_currentEncoding;
+    return this->m_doOverrideEncoder ? this->m_overrideEncoder : this->m_currentEncoding;
 }
 
 void MainWindow::configureStreamEncoding(QTextStream &textStream)
 {
-    QTextCodec *encoder = this->getEncoder();
-    if (Q_LIKELY(encoder)) // should be true
-        textStream.setCodec(encoder);
-    else
-        qWarning("The encoder variable should not be null.");
+    textStream.setEncoding(this->getEncoder());
 
     textStream.setGenerateByteOrderMark(this->m_encoderBom);
 }
 
 void MainWindow::configureStreamDecoding(QTextStream &textStream)
 {
-    if (m_overrideDecoder) {
-        textStream.setCodec(m_overrideDecoder);
-    }
+    if(m_doOverrideDecoder)
+        textStream.setEncoding(m_overrideDecoder);
     textStream.setAutoDetectUnicode(true);
 }
 
diff --git a/app/mainwindow.h b/app/mainwindow.h
index 02c7391..aa76156 100644
--- a/app/mainwindow.h
+++ b/app/mainwindow.h
@@ -43,6 +43,7 @@ class QDockWidget;
 class QLabel;
 class QMenu;
 class QToolButton;
+class QTextCodec;
 
 class Action;
 class ConfigDialog;
@@ -134,7 +135,7 @@ private Q_SLOTS:
     /// Change the codec for the current document
     /// @param isUserRequest set to true if the user requested the changement (in this case, the
     /// application should warn the user -- not implemented yet.).
-    void setCurrentEncoding(QTextCodec *codec /*, bool isUserRequest = false */);
+    void setCurrentEncoding(QStringConverter::Encoding codec );
 
 private:
     void createActions();
@@ -225,15 +226,17 @@ private:
     QPointer<ConfigDialog> m_configDialog;
 
     QUrl m_currentUrl;
-    QTextCodec *m_currentEncoding;
-    /// If not null, override the encoder (rather than @ref m_currentEncoding)
-    QTextCodec *m_overrideEncoder;
-    /// If not null, override the decoder
-    QTextCodec *m_overrideDecoder;
+    QStringConverter::Encoding m_currentEncoding;
+    /// If true, override the encoder (rather than @ref m_currentEncoding)
+    bool m_doOverrideEncoder;
+    QStringConverter::Encoding m_overrideEncoder;
+    /// If true, override the decoder
+    bool m_doOverrideDecoder;
+    QStringConverter::Encoding m_overrideDecoder;
     /// True if a BOM must be added to the PGF-file
     bool m_encoderBom;
     /// Return the current encoder (m_currentEncoding or another if encoder is overriden).
-    /*virtual*/ QTextCodec *getEncoder() const;
+    /*virtual*/ QStringConverter::Encoding getEncoder() const;
 
     QUrl m_lastUrl;
     QDateTime m_lastInternalModifiedDateTime;
diff --git a/app/tikzcommandinserter.cpp b/app/tikzcommandinserter.cpp
index 470c743..73cc9e4 100644
--- a/app/tikzcommandinserter.cpp
+++ b/app/tikzcommandinserter.cpp
@@ -46,7 +46,7 @@
 #include "tikzcommandwidget.h"
 #include "../common/utils/combobox.h"
 
-static const QString s_completionPlaceHolder(0x2022);
+static const QString s_completionPlaceHolder(QChar(0x2022));
 
 TikzCommandList TikzCommandInserter::m_tikzSections;
 QList<TikzCommand> TikzCommandInserter::m_tikzCommandsList;
@@ -90,10 +90,10 @@ static TikzCommand newCommand(const QString &name, const QString &description,
 static QString translateOptions(const QString &text)
 {
     QString translatedText;
-    for (int pos = 0, oldPos = 0; pos >= 0;) {
+    for (qsizetype pos = 0, oldPos = 0; pos >= 0;) {
         oldPos = pos;
         pos = text.indexOf(QLatin1Char('<'), pos); // option is between < and >
-        translatedText += text.midRef(
+        translatedText += text.mid(
                 oldPos, pos - oldPos + 1); // add text between the current option and the previous
                                            // option; this also adds the end of the original string,
                                            // except when there are no options
@@ -574,7 +574,7 @@ QDockWidget *TikzCommandInserter::getDockWidget(QWidget *parent)
     tikzLayout->addWidget(commandsComboLabel, 0, 0);
     tikzLayout->addWidget(m_commandsCombo, 0, 1);
     tikzLayout->addWidget(m_commandsStack, 1, 0, 1, 2);
-    tikzLayout->setMargin(5);
+    tikzLayout->setContentsMargins(5, 5, 5, 5);
 
     TikzCommandWidget *tikzWidget = new TikzCommandWidget;
     tikzWidget->setLayout(tikzLayout);
@@ -801,7 +801,7 @@ void TikzCommandInserter::insertTag(const QString &tag, int dx, int dy)
 
         // replace all options (between <...>) by a place holder
         QString insertWord = tag;
-        const QRegExp rx(QLatin1String("<[^<>]*>"));
+        const QRegularExpression rx(QLatin1String("<[^<>]*>"));
         insertWord.replace(rx, s_completionPlaceHolder);
 
         QTextCursor cur = m_mainEdit->textCursor();
diff --git a/app/tikzeditor.cpp b/app/tikzeditor.cpp
index aa7fa8d..81b8929 100644
--- a/app/tikzeditor.cpp
+++ b/app/tikzeditor.cpp
@@ -50,7 +50,7 @@
 
 #include "linenumberwidget.h"
 
-static const QString s_completionPlaceHolder(0x2022);
+static const QString s_completionPlaceHolder(QChar(0x2022));
 
 TikzEditor::TikzEditor(QWidget *parent)
     : QPlainTextEdit(parent),
@@ -619,8 +619,8 @@ void TikzEditor::insertCompletion(const QString &completion)
 
     // remove all options (between <...>) and put cursor at the first option
     QString insertWord = completion.right(extra);
-    const QRegExp rx(QLatin1String("<[^<>]*>"));
-    const int offset = rx.indexIn(insertWord) - 1; // put cursor at the first option
+    const QRegularExpression rx(QLatin1String("<[^<>]*>"));
+    const int offset = insertWord.indexOf(rx) - 1; // put cursor at the first option
     insertWord.replace(rx, s_completionPlaceHolder);
 
     cursor.insertText(insertWord);
diff --git a/app/tikzeditorhighlighter.h b/app/tikzeditorhighlighter.h
index 6db5ee3..5352c2e 100644
--- a/app/tikzeditorhighlighter.h
+++ b/app/tikzeditorhighlighter.h
@@ -22,6 +22,7 @@
 #define TIKZEDITORHIGHLIGHTER_H
 
 #include <QtGui/QSyntaxHighlighter>
+#include <QtCore5Compat/QRegExp>
 
 struct HighlightingRule
 {
diff --git a/app/tikzeditorview.cpp b/app/tikzeditorview.cpp
index ffb79ef..e349edf 100644
--- a/app/tikzeditorview.cpp
+++ b/app/tikzeditorview.cpp
@@ -59,7 +59,7 @@ TikzEditorView::TikzEditorView(QWidget *parent)
 
     QVBoxLayout *mainLayout = new QVBoxLayout(this);
     mainLayout->setSpacing(0);
-    mainLayout->setMargin(0);
+    mainLayout->setContentsMargins(0, 0, 0, 0);
     mainLayout->addWidget(m_tikzEditor);
 
     createActions();
diff --git a/app/usercommandeditdialog.cpp b/app/usercommandeditdialog.cpp
index 02d72d5..ca194af 100644
--- a/app/usercommandeditdialog.cpp
+++ b/app/usercommandeditdialog.cpp
@@ -20,7 +20,7 @@
 
 #include <QtCore/QSettings>
 
-static const QString s_completionPlaceHolder(0x2022);
+static const QString s_completionPlaceHolder(QChar(0x2022));
 
 UserCommandEditDialog::UserCommandEditDialog(QWidget *parent) : QDialog(parent), m_oldIndex(-1)
 {
diff --git a/app/usercommandinserter.cpp b/app/usercommandinserter.cpp
index 42943c7..8151ca9 100644
--- a/app/usercommandinserter.cpp
+++ b/app/usercommandinserter.cpp
@@ -25,7 +25,7 @@
 #include "tikzcommandinserter.h"
 #include "usercommandeditdialog.h"
 
-static const QString s_completionPlaceHolder(0x2022);
+static const QString s_completionPlaceHolder(QChar(0x2022));
 
 UserCommandInserter::UserCommandInserter(QWidget *parent) : QObject(parent), m_userMenu(0)
 {
diff --git a/common/common.pri b/common/common.pri
index dd3aa7f..d4f05fc 100644
--- a/common/common.pri
+++ b/common/common.pri
@@ -1,4 +1,5 @@
 QT *= widgets printsupport
+greaterThan(QT_MAJOR_VERSION, 6): QT *= core5compat
 
 include($${_PRO_FILE_PWD_}/qmake/findpoppler.pri)
 
diff --git a/common/tikzpreview.cpp b/common/tikzpreview.cpp
index 8be3574..cd3573b 100644
--- a/common/tikzpreview.cpp
+++ b/common/tikzpreview.cpp
@@ -18,11 +18,10 @@
 
 #include "tikzpreview.h"
 
-#include <poppler-qt5.h>
+#include <poppler-qt6.h>
 
 #include <QSettings>
 #include <QApplication>
-#include <QDesktopWidget>
 #include <QGraphicsProxyWidget>
 #include <QMenu>
 #include <QScreen>
@@ -316,13 +315,12 @@ void TikzPreview::pixmapUpdated(Poppler::Document *tikzPdfDoc, const QList<qreal
 
 QImage TikzPreview::renderToImage(double xres, double yres, int pageNumber)
 {
-    Poppler::Page *page = m_tikzPdfDoc->page(pageNumber);
+    auto page = m_tikzPdfDoc->page(pageNumber);
     //	const QSizeF pageSize = page->pageSizeF();
     //	const QImage image = pageSize.height() >= pageSize.width()
     //		? page->renderToImage(xres, yres)
     //		: page->renderToImage(xres, yres, -1, -1, -1, -1, Poppler::Page::Rotate270); // slow
     const QImage image = page->renderToImage(xres, yres); // slow
-    delete page;
     return image;
 }
 
diff --git a/common/tikzpreviewcontroller.cpp b/common/tikzpreviewcontroller.cpp
index e6329f4..f4d090d 100644
--- a/common/tikzpreviewcontroller.cpp
+++ b/common/tikzpreviewcontroller.cpp
@@ -33,7 +33,7 @@
 #include <QtWidgets/QMenu>
 #include <QtWidgets/QPushButton>
 
-#include <poppler-qt5.h>
+#include <poppler-qt6.h>
 
 #include "templatewidget.h"
 #include "tikzpreview.h"
diff --git a/common/tikzpreviewgenerator.cpp b/common/tikzpreviewgenerator.cpp
index 548d67e..5919f04 100644
--- a/common/tikzpreviewgenerator.cpp
+++ b/common/tikzpreviewgenerator.cpp
@@ -32,7 +32,8 @@
 #include <QtGui/QPixmap>
 #include <QtCore/QStandardPaths>
 #include <QtWidgets/QPlainTextEdit>
-#include <poppler-qt5.h>
+#include <QtCore5Compat/QRegExp>
+#include <poppler-qt6.h>
 
 #include "tikzpreviewcontroller.h"
 #include "mainwidget.h"
@@ -306,7 +307,7 @@ void TikzPreviewGenerator::createPreview()
             // Update widget
             if (m_tikzPdfDoc)
                 delete m_tikzPdfDoc;
-            m_tikzPdfDoc = Poppler::Document::load(tikzPdfFileInfo.absoluteFilePath());
+            m_tikzPdfDoc = Poppler::Document::load(tikzPdfFileInfo.absoluteFilePath()).release();
             if (m_tikzPdfDoc) {
                 m_shortLogText = QLatin1String("[LaTeX] ")
                         + tr("Process finished successfully.", "info process");
diff --git a/common/tikzpreviewmessagewidget.cpp b/common/tikzpreviewmessagewidget.cpp
index 432d818..5daf551 100644
--- a/common/tikzpreviewmessagewidget.cpp
+++ b/common/tikzpreviewmessagewidget.cpp
@@ -55,7 +55,7 @@ TikzPreviewMessageWidget::TikzPreviewMessageWidget(QWidget *parent) : QFrame(par
                                         "}")));
 
     QHBoxLayout *infoLayout = new QHBoxLayout(this);
-    infoLayout->setMargin(10);
+    infoLayout->setContentsMargins(10, 10 ,10, 10);
     infoLayout->addWidget(m_infoPixmapLabel);
     infoLayout->addWidget(m_infoLabel);
 
diff --git a/common/tikzpreviewrenderer.cpp b/common/tikzpreviewrenderer.cpp
index 372bea4..e97fe11 100644
--- a/common/tikzpreviewrenderer.cpp
+++ b/common/tikzpreviewrenderer.cpp
@@ -19,7 +19,7 @@
 #include "tikzpreviewrenderer.h"
 
 #include <QtGui/QImage>
-#include <poppler-qt5.h>
+#include <poppler-qt6.h>
 
 TikzPreviewRenderer::TikzPreviewRenderer()
 {
@@ -38,9 +38,8 @@ TikzPreviewRenderer::~TikzPreviewRenderer()
 void TikzPreviewRenderer::generatePreview(Poppler::Document *tikzPdfDoc, qreal zoomFactor,
                                           int currentPage)
 {
-    Poppler::Page *pdfPage = tikzPdfDoc->page(currentPage);
+    auto pdfPage = tikzPdfDoc->page(currentPage);
     const QImage tikzImage = pdfPage->renderToImage(zoomFactor * 72, zoomFactor * 72);
-    delete pdfPage;
 
     Q_EMIT showPreview(tikzImage, zoomFactor);
 }
diff --git a/common/utils/pagedialog.cpp b/common/utils/pagedialog.cpp
index 5585de9..32f3042 100644
--- a/common/utils/pagedialog.cpp
+++ b/common/utils/pagedialog.cpp
@@ -101,7 +101,7 @@ QWidget *PageDialog::centerWidget()
     m_pagesTitleLabel->setStyleSheet(QLatin1String("QLabel { font-weight: bold; }"));
     QGridLayout *titleLayout = new QGridLayout(titleFrame);
     titleLayout->setColumnStretch(0, 1);
-    titleLayout->setMargin(6);
+    titleLayout->setContentsMargins(6, 6, 6, 6);
     titleLayout->addWidget(m_pagesTitleLabel);
 
     // add pages
diff --git a/common/utils/recentfilesaction.cpp b/common/utils/recentfilesaction.cpp
index 48bfeed..7a45a3e 100644
--- a/common/utils/recentfilesaction.cpp
+++ b/common/utils/recentfilesaction.cpp
@@ -102,7 +102,7 @@ void RecentFilesAction::openRecentFile()
 #  ifdef Q_OS_WIN32
         Q_EMIT urlSelected(Url(action->data().toString()));
 #  else
-        Q_EMIT urlSelected(Url(QLatin1String("file://") + action->data().toString()));
+        Q_EMIT urlSelected(QUrl(QLatin1String("file://") + action->data().toString()));
 #  endif
 }
 
diff --git a/common/utils/recentfilesaction.h b/common/utils/recentfilesaction.h
index 0694ea9..3de53a5 100644
--- a/common/utils/recentfilesaction.h
+++ b/common/utils/recentfilesaction.h
@@ -60,7 +60,7 @@ public:
     void removeUrl(const QUrl &url);
 
 Q_SIGNALS:
-    void urlSelected(const Url &url);
+    void urlSelected(const QUrl &url);
 
 private Q_SLOTS:
     void openRecentFile();
diff --git a/common/utils/standardaction.cpp b/common/utils/standardaction.cpp
index e78cba8..3b54b80 100644
--- a/common/utils/standardaction.cpp
+++ b/common/utils/standardaction.cpp
@@ -308,7 +308,7 @@ RecentFilesAction *openRecent(const QObject *recvr, const char *slot, QObject *p
     RecentFilesAction *action = new RecentFilesAction(
             Icon(QLatin1String("document-open-recent")),
             QCoreApplication::translate("StandardAction", "&Open Recent"), parent);
-    QObject::connect(action, SIGNAL(urlSelected(Url)), recvr, slot);
+    QObject::connect(action, SIGNAL(urlSelected(QUrl)), recvr, slot);
     return action;
 }
 Action *save(const QObject *recvr, const char *slot, QObject *parent)
diff --git a/common/utils/toggleaction.h b/common/utils/toggleaction.h
index a4efa49..7d9064f 100644
--- a/common/utils/toggleaction.h
+++ b/common/utils/toggleaction.h
@@ -36,7 +36,7 @@ public:
 };
 #else
 #  include <QtCore/QtGlobal>
-#  include <QtWidgets/QAction>
+#  include <QAction>
 
 class ToggleAction : public QAction
 {
diff --git a/common/utils/urlcompletion.h b/common/utils/urlcompletion.h
index 0694b5c..4360e20 100644
--- a/common/utils/urlcompletion.h
+++ b/common/utils/urlcompletion.h
@@ -29,7 +29,7 @@ public:
 };
 #else
 #  include <QtWidgets/QCompleter>
-#  include <QtWidgets/QFileSystemModel>
+#  include <QFileSystemModel>
 
 class UrlCompletion : public QCompleter
 {
diff --git a/common/utils/zoomaction.cpp b/common/utils/zoomaction.cpp
index 902674f..c192633 100644
--- a/common/utils/zoomaction.cpp
+++ b/common/utils/zoomaction.cpp
@@ -18,6 +18,7 @@
 
 #include "zoomaction.h"
 
+#include <QRegularExpression>
 #include "globallocale.h"
 #include "icon.h"
 
@@ -136,7 +137,7 @@ void ZoomAction::setZoomFactor(const QString &zoomFactorText)
 {
     setZoomFactor(GlobalLocale::readNumber(
                           QString(zoomFactorText)
-                                  .remove(QRegExp(QString(QLatin1String("[^\\d\\%1]*"))
+                                  .remove(QRegularExpression(QString(QLatin1String("[^\\d\\%1]*"))
                                                           .arg(GlobalLocale::decimalSymbol()))))
                   / 100.0);
 }
diff --git a/qmake/findpoppler.pri b/qmake/findpoppler.pri
index f30eddc..1a95677 100644
--- a/qmake/findpoppler.pri
+++ b/qmake/findpoppler.pri
@@ -1,7 +1,7 @@
 unix: {
 	PKG_CONFIG = $$pkgConfigExecutable()
-    POPPLERINCLUDES = $$system($$PKG_CONFIG --cflags poppler-qt5)
-    POPPLERLIBS = $$system($$PKG_CONFIG --libs poppler-qt5)
+    POPPLERINCLUDES = $$system($$PKG_CONFIG --cflags poppler-qt6)
+    POPPLERLIBS = $$system($$PKG_CONFIG --libs poppler-qt6)
 	QMAKE_CXXFLAGS += $$POPPLERINCLUDES
 	QMAKE_LFLAGS += $$POPPLERLIBS
 }
@@ -11,4 +11,4 @@ win32 {
 	LIBS += -L$${_PRO_FILE_PWD_}/win32/poppler/
 }
 
-LIBS += -lpoppler-qt5
+LIBS += -lpoppler-qt6