diff --git a/QupZilla.pro b/QupZilla.pro
index 8c3cebe74..0def652db 100644
--- a/QupZilla.pro
+++ b/QupZilla.pro
@@ -6,8 +6,8 @@
 #
 #-------------------------------------------------
 
-lessThan(QT_VERSION, 4.7) {
-    error("QupZilla requires at least Qt 4.7!")
+lessThan(QT_VERSION, 5.4) {
+    error("QupZilla requires at least Qt 5.4!")
 }
 
 # Create plugins directory first on Mac / Linux
diff --git a/src/defines.pri b/src/defines.pri
index b10564c4e..95e9c5fd2 100644
--- a/src/defines.pri
+++ b/src/defines.pri
@@ -60,48 +60,6 @@ haiku-* {
     DEFINES *= NO_X11
 }
 
-# Check for pkg-config availability
-!mac:unix:system(pkg-config --version > /dev/null) {
-    isEqual(QT_MAJOR_VERSION, 5) {
-        MODNAME = Qt5WebKitWidgets
-    }
-    else {
-        MODNAME = QtWebKit
-    }
-
-    QTWEBKIT_VERSION = $$system(PKG_CONFIG_PATH="$$[QT_INSTALL_LIBS]/pkgconfig" pkg-config --modversion $$MODNAME)
-    QTWEBKIT_VERSION_MAJOR = $$section(QTWEBKIT_VERSION, ".", 0, 0)
-    QTWEBKIT_VERSION_MINOR = $$section(QTWEBKIT_VERSION, ".", 1, 1)
-
-    isEqual(QT_MAJOR_VERSION, 5) {
-        greaterThan(QTWEBKIT_VERSION_MAJOR, 4) {
-            # There is one Qt5WebKitWidgets version now, which has same features as QtWebKit 2.3
-            DEFINES *= USE_QTWEBKIT_2_2 USE_QTWEBKIT_2_3
-        }
-    }
-    else { # Qt 4
-        equals(QTWEBKIT_VERSION_MAJOR, 4):greaterThan(QTWEBKIT_VERSION_MINOR, 8) {
-            # 4.9.x = QtWebKit 2.2
-            DEFINES *= USE_QTWEBKIT_2_2
-        }
-
-        equals(QTWEBKIT_VERSION_MAJOR, 4):greaterThan(QTWEBKIT_VERSION_MINOR, 9) {
-            # 4.10.x = QtWebKit 2.3
-            DEFINES *= USE_QTWEBKIT_2_3
-        }
-    }
-}
-else {
-    isEqual(QT_VERSION, 4.8.0)|greaterThan(QT_VERSION, 4.8.0) {
-        DEFINES *= USE_QTWEBKIT_2_2
-    }
-
-    isEqual(QT_MAJOR_VERSION, 5) {
-        DEFINES *= USE_QTWEBKIT_2_2 USE_QTWEBKIT_2_3
-    }
-}
-
-
 !mac:unix {
     binary_folder = /usr/bin
     library_folder = /usr/lib
@@ -140,8 +98,7 @@ isEmpty(QMAKE_LRELEASE) {
 
     # Try to use lrelease from PATH
     unix:!exists($$QMAKE_LRELEASE) {
-        isEqual(QT_MAJOR_VERSION, 4): QMAKE_LRELEASE = lrelease-qt4
-        else: QMAKE_LRELEASE = lrelease
+        QMAKE_LRELEASE = lrelease
     }
 }
 
diff --git a/src/lib/3rdparty/lineedit.cpp b/src/lib/3rdparty/lineedit.cpp
index a56bc45ea..2c4b339c8 100644
--- a/src/lib/3rdparty/lineedit.cpp
+++ b/src/lib/3rdparty/lineedit.cpp
@@ -27,10 +27,6 @@
 #include <QStyleOption>
 #include <QApplication>
 
-#if QT_VERSION < 0x050000
-#include <QInputContext>
-#endif
-
 SideWidget::SideWidget(QWidget* parent)
     : QWidget(parent)
 {
@@ -208,16 +204,6 @@ QMenu* LineEdit::createContextMenu()
     popup->addSeparator();
     popup->addAction(m_editActions[SelectAll]);
 
-#if !defined(QT_NO_IM) && QT_VERSION < 0x050000
-    QInputContext* qic = inputContext();
-    if (qic) {
-        QList<QAction*> imActions = qic->actions();
-        for (int i = 0; i < imActions.size(); ++i) {
-            popup->addAction(imActions.at(i));
-        }
-    }
-#endif
-
     // Hack to get QUnicodeControlCharacterMenu
     QMenu* tmp = createStandardContextMenu();
     tmp->setParent(popup);
diff --git a/src/lib/3rdparty/qtwin.cpp b/src/lib/3rdparty/qtwin.cpp
index 0dc14cdad..8ea82ef33 100644
--- a/src/lib/3rdparty/qtwin.cpp
+++ b/src/lib/3rdparty/qtwin.cpp
@@ -84,11 +84,7 @@ public:
     void removeWidget(QWidget* widget) {
         widgets.removeAll(widget);
     }
-#if (QT_VERSION < 0x050000)
-    bool winEvent(MSG* message, long* result);
-#else
     bool nativeEvent(const QByteArray &eventType, void* _message, long* result);
-#endif
 
 private:
     QWidgetList widgets;
@@ -272,15 +268,10 @@ WindowNotifier* QtWin::windowNotifier()
 
 
 /* Notify all enabled windows that the DWM state changed */
-#if (QT_VERSION < 0x050000)
-bool WindowNotifier::winEvent(MSG* message, long* result)
-{
-#else
 bool WindowNotifier::nativeEvent(const QByteArray &eventType, void* _message, long* result)
 {
     Q_UNUSED(eventType)
     MSG* message = static_cast<MSG*>(_message);
-#endif
     if (message && message->message == WM_DWMCOMPOSITIONCHANGED) {
         bool compositionEnabled = QtWin::isCompositionEnabled();
         foreach (QWidget* widget, widgets) {
@@ -296,11 +287,7 @@ bool WindowNotifier::nativeEvent(const QByteArray &eventType, void* _message, lo
             }
         }
     }
-#if (QT_VERSION < 0x050000)
-    return QWidget::winEvent(message, result);
-#else
     return QWidget::nativeEvent(eventType, _message, result);
-#endif
 }
 
 #ifdef W7API
diff --git a/src/lib/adblock/adblockrule.cpp b/src/lib/adblock/adblockrule.cpp
index 24a224f63..37de3b1f6 100644
--- a/src/lib/adblock/adblockrule.cpp
+++ b/src/lib/adblock/adblockrule.cpp
@@ -59,7 +59,6 @@
 // count .co.uk (and others) as second-level domain
 static QString toSecondLevelDomain(const QUrl &url)
 {
-#if QT_VERSION >= 0x040800
     const QString topLevelDomain = url.topLevelDomain();
     const QString urlHost = url.host();
 
@@ -78,19 +77,6 @@ static QString toSecondLevelDomain(const QUrl &url)
     }
 
     return domain + topLevelDomain;
-#else
-    QString domain = url.host();
-
-    if (domain.count(QL1C('.')) == 0) {
-        return QString();
-    }
-
-    while (domain.count(QL1C('.')) != 1) {
-        domain = domain.mid(domain.indexOf(QL1C('.')) + 1);
-    }
-
-    return domain;
-#endif
 }
 
 AdBlockRule::AdBlockRule(const QString &filter, AdBlockSubscription* subscription)
diff --git a/src/lib/app/browserwindow.cpp b/src/lib/app/browserwindow.cpp
index 64efd06e9..6ac820416 100644
--- a/src/lib/app/browserwindow.cpp
+++ b/src/lib/app/browserwindow.cpp
@@ -89,10 +89,6 @@
 #include <QToolTip>
 #include <QScrollArea>
 
-#if QT_VERSION < 0x050000
-#include "qwebkitversion.h"
-#endif
-
 #ifdef QZ_WS_X11
 #include <X11/Xlib.h>
 #include <X11/Xatom.h>
@@ -1671,15 +1667,10 @@ void BrowserWindow::applyBlurToMainWindow(bool force)
     QtWin::extendFrameIntoClientArea(this, leftMargin, topMargin, rightMargin, bottomMargin);
 }
 
-#if (QT_VERSION < 0x050000)
-bool BrowserWindow::winEvent(MSG* message, long* result)
-{
-#else
 bool BrowserWindow::nativeEvent(const QByteArray &eventType, void* _message, long* result)
 {
     Q_UNUSED(eventType)
     MSG* message = static_cast<MSG*>(_message);
-#endif
     if (message && message->message == WM_DWMCOMPOSITIONCHANGED) {
         Settings settings;
         settings.beginGroup("Browser-View-Settings");
@@ -1716,11 +1707,7 @@ bool BrowserWindow::nativeEvent(const QByteArray &eventType, void* _message, lon
             m_useTransparentBackground = false;
         }
     }
-#if (QT_VERSION < 0x050000)
-    return QMainWindow::winEvent(message, result);
-#else
     return QMainWindow::nativeEvent(eventType, _message, result);
-#endif
 }
 
 void BrowserWindow::paintEvent(QPaintEvent* event)
diff --git a/src/lib/app/browserwindow.h b/src/lib/app/browserwindow.h
index 693651320..54dbc551c 100644
--- a/src/lib/app/browserwindow.h
+++ b/src/lib/app/browserwindow.h
@@ -231,11 +231,7 @@ private slots:
     void applyBlurToMainWindow(bool force = false);
 
 private:
-#if (QT_VERSION < 0x050000)
-    bool winEvent(MSG* message, long* result);
-#else
     bool nativeEvent(const QByteArray &eventType, void* _message, long* result);
-#endif
 
     void paintEvent(QPaintEvent* event);
     bool eventFilter(QObject* object, QEvent* event);
diff --git a/src/lib/app/datapaths.cpp b/src/lib/app/datapaths.cpp
index 05a5f10aa..3cee88282 100644
--- a/src/lib/app/datapaths.cpp
+++ b/src/lib/app/datapaths.cpp
@@ -21,11 +21,7 @@
 #include <QApplication>
 #include <QDir>
 
-#if QT_VERSION < 0x050000
-#include <QDesktopServices>
-#else
 #include <QStandardPaths>
-#endif
 
 Q_GLOBAL_STATIC(DataPaths, qz_data_paths)
 
@@ -104,11 +100,7 @@ void DataPaths::init()
     // Config
 #if defined(Q_OS_WIN) || defined(Q_OS_OS2)
     // Use %LOCALAPPDATA%/qupzilla as Config path on Windows
-#if QT_VERSION < 0x050000
-    QString dataLocation = QDesktopServices::storageLocation(QDesktopServices::DataLocation);
-#else
     QString dataLocation = QStandardPaths::writableLocation(QStandardPaths::DataLocation);
-#endif
     // Backwards compatibility
     if (dataLocation.isEmpty()) {
         dataLocation = QDir::homePath() + QLatin1String("/.config/qupzilla");
diff --git a/src/lib/app/mainapplication.cpp b/src/lib/app/mainapplication.cpp
index 31d91f8f1..db7d83662 100644
--- a/src/lib/app/mainapplication.cpp
+++ b/src/lib/app/mainapplication.cpp
@@ -62,11 +62,7 @@
 #include <QTimer>
 #include <QDir>
 
-#if QT_VERSION < 0x050000
-#include "qwebkitversion.h"
-#else
 #include <QStandardPaths>
-#endif
 
 #if defined(Q_OS_WIN) && !defined(Q_OS_OS2)
 #include "registerqappassociation.h"
@@ -101,9 +97,7 @@ MainApplication::MainApplication(int &argc, char** argv)
     , m_registerQAppAssociation(0)
 #endif
 {
-#if QT_VERSION >= 0x050000
     setAttribute(Qt::AA_UseHighDpiPixmaps, true);
-#endif
 
     setApplicationName(QLatin1String("QupZilla"));
     setApplicationVersion(Qz::VERSION);
diff --git a/src/lib/app/qzcommon.h b/src/lib/app/qzcommon.h
index 8c77dfcc3..d8560f524 100644
--- a/src/lib/app/qzcommon.h
+++ b/src/lib/app/qzcommon.h
@@ -37,11 +37,7 @@
 #endif
 
 #ifndef QSL
-#if QT_VERSION >= 0x050000
 #define QSL(x) QStringLiteral(x)
-#else
-#define QSL(x) QLatin1String(x)
-#endif
 #endif
 
 #ifndef QL1S
diff --git a/src/lib/autofill/autofill.cpp b/src/lib/autofill/autofill.cpp
index efc7aca72..bb5630da5 100644
--- a/src/lib/autofill/autofill.cpp
+++ b/src/lib/autofill/autofill.cpp
@@ -32,9 +32,7 @@
 #include <QXmlStreamReader>
 #include <QNetworkRequest>
 
-#if QT_VERSION >= 0x050000
 #include <QUrlQuery>
-#endif
 
 AutoFill::AutoFill(QObject* parent)
     : QObject(parent)
diff --git a/src/lib/autofill/pageformcompleter.cpp b/src/lib/autofill/pageformcompleter.cpp
index fac0127c6..0cb774901 100644
--- a/src/lib/autofill/pageformcompleter.cpp
+++ b/src/lib/autofill/pageformcompleter.cpp
@@ -19,9 +19,7 @@
 #include "qzregexp.h"
 
 #include <QWebEnginePage>
-#if QT_VERSION >= 0x050000
 #include <QUrlQuery>
-#endif
 
 PageFormCompleter::PageFormCompleter()
     : m_page(0)
@@ -247,13 +245,9 @@ PageFormCompleter::QueryItems PageFormCompleter::createQueryItems(QByteArray dat
     // QUrlQuery/QUrl never encodes/decodes + and spaces
     data.replace('+', ' ');
 
-#if QT_VERSION >= 0x050000
     QUrlQuery query;
     query.setQuery(data);
     QueryItems arguments = query.queryItems(QUrl::FullyDecoded);
-#else
-    QueryItems arguments = QUrl::fromEncoded("http://foo.com/?" + data).queryItems();
-#endif
 
     return arguments;
 }
diff --git a/src/lib/downloads/downloadfilehelper.cpp b/src/lib/downloads/downloadfilehelper.cpp
index 446a21daa..3762e6bde 100644
--- a/src/lib/downloads/downloadfilehelper.cpp
+++ b/src/lib/downloads/downloadfilehelper.cpp
@@ -34,11 +34,7 @@
 #include <QWebEngineHistory>
 #include <QFileDialog>
 
-#if QT_VERSION >= 0x050000
 #include <QStandardPaths>
-#else
-#include <QDesktopServices>
-#endif
 
 DownloadFileHelper::DownloadFileHelper(const QString &lastDownloadPath, const QString &downloadPath, bool useNativeDialog)
     : QObject()
@@ -229,22 +225,12 @@ void DownloadFileHelper::optionsDialogAccepted(int finish)
                 dialog->selectFile(m_h_fileName);
 
                 QList<QUrl> urls;
-                urls <<
-#if QT_VERSION >= 0x050000
-                     QUrl::fromLocalFile(QStandardPaths::writableLocation(QStandardPaths::HomeLocation))
+                urls << QUrl::fromLocalFile(QStandardPaths::writableLocation(QStandardPaths::HomeLocation))
                      << QUrl::fromLocalFile(QStandardPaths::writableLocation(QStandardPaths::DesktopLocation))
                      << QUrl::fromLocalFile(QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation))
                      << QUrl::fromLocalFile(QStandardPaths::writableLocation(QStandardPaths::PicturesLocation))
                      << QUrl::fromLocalFile(QStandardPaths::writableLocation(QStandardPaths::MusicLocation))
                      << QUrl::fromLocalFile(QStandardPaths::writableLocation(QStandardPaths::MoviesLocation));
-#else
-                     QUrl::fromLocalFile(QDesktopServices::storageLocation(QDesktopServices::HomeLocation))
-                     << QUrl::fromLocalFile(QDesktopServices::storageLocation(QDesktopServices::DesktopLocation))
-                     << QUrl::fromLocalFile(QDesktopServices::storageLocation(QDesktopServices::DocumentsLocation))
-                     << QUrl::fromLocalFile(QDesktopServices::storageLocation(QDesktopServices::PicturesLocation))
-                     << QUrl::fromLocalFile(QDesktopServices::storageLocation(QDesktopServices::MusicLocation))
-                     << QUrl::fromLocalFile(QDesktopServices::storageLocation(QDesktopServices::MoviesLocation));
-#endif
                 dialog->setSidebarUrls(urls);
 
                 dialog->open();
diff --git a/src/lib/downloads/downloaditem.cpp b/src/lib/downloads/downloaditem.cpp
index ae352f21a..abc81c6c0 100644
--- a/src/lib/downloads/downloaditem.cpp
+++ b/src/lib/downloads/downloaditem.cpp
@@ -201,10 +201,6 @@ void DownloadItem::finished()
     }
 
     m_item->setSizeHint(sizeHint());
-#if QT_VERSION == 0x040700 // Workaround
-    ui->button->show();
-    ui->button->hide();
-#endif
     m_downloading = false;
 
     if (m_openAfterFinish) {
@@ -353,10 +349,6 @@ void DownloadItem::stop(bool askForDeleteFile)
     ui->button->hide();
     m_item->setSizeHint(sizeHint());
 
-#if QT_VERSION == 0x040700 // Workaround
-    ui->button->show();
-    ui->button->hide();
-#endif
     m_downloading = false;
 
     emit downloadFinished(false);
diff --git a/src/lib/downloads/downloadmanager.cpp b/src/lib/downloads/downloadmanager.cpp
index 9d00529d1..3cf5dcbb0 100644
--- a/src/lib/downloads/downloadmanager.cpp
+++ b/src/lib/downloads/downloadmanager.cpp
@@ -123,15 +123,10 @@ void DownloadManager::startExternalManager(const QUrl &url)
 }
 
 #ifdef W7TASKBAR
-#if (QT_VERSION < 0x050000)
-bool DownloadManager::winEvent(MSG* message, long* result)
-{
-#else
 bool DownloadManager::nativeEvent(const QByteArray &eventType, void* _message, long* result)
 {
     Q_UNUSED(eventType)
     MSG* message = static_cast<MSG*>(_message);
-#endif
     return win7.winEvent(message, result);
 }
 #endif
diff --git a/src/lib/downloads/downloadmanager.h b/src/lib/downloads/downloadmanager.h
index a3f570d4c..1d0db843f 100644
--- a/src/lib/downloads/downloadmanager.h
+++ b/src/lib/downloads/downloadmanager.h
@@ -83,12 +83,8 @@ public slots:
 
 #ifdef W7TASKBAR
 protected:
-#if (QT_VERSION < 0x050000)
-    virtual bool winEvent(MSG* message, long* result);
-#else
     virtual bool nativeEvent(const QByteArray &eventType, void* _message, long* result);
 #endif
-#endif
 
 private slots:
     void clearList();
diff --git a/src/lib/lib.pro b/src/lib/lib.pro
index 09a7936da..4a2203b28 100644
--- a/src/lib/lib.pro
+++ b/src/lib/lib.pro
@@ -1,8 +1,4 @@
-isEqual(QT_MAJOR_VERSION, 5) {
-    QT += webenginewidgets network widgets printsupport sql script gui-private
-} else {
-    QT += core gui webkit sql network script concurrent
-}
+QT += webenginewidgets network widgets printsupport sql script gui-private
 
 TARGET = QupZilla
 TEMPLATE = lib
@@ -231,6 +227,7 @@ SOURCES += \
     tools/pagethumbnailer.cpp \
     tools/plaineditwithlines.cpp \
     tools/progressbar.cpp \
+    tools/qzregexp.cpp \
     tools/qztools.cpp \
     tools/sqldatabase.cpp \
     tools/toolbutton.cpp \
@@ -434,6 +431,7 @@ HEADERS  += \
     tools/pagethumbnailer.h \
     tools/plaineditwithlines.h \
     tools/progressbar.h \
+    tools/qzregexp.h \
     tools/qztools.h \
     tools/sqldatabase.h \
     tools/toolbutton.h \
@@ -509,14 +507,10 @@ RESOURCES += \
     data/icons.qrc \
     data/oxygen-fallback.qrc
 
-isEqual(QT_MAJOR_VERSION, 5) {
-    qtHaveModule(ftp) {
-        QT *= ftp
-    } else {
-        include(3rdparty/qftp/qftp.pri)
-    }
-
-    SOURCES += tools/qzregexp.cpp
+qtHaveModule(ftp) {
+    QT *= ftp
+} else {
+    include(3rdparty/qftp/qftp.pri)
 }
 
 !mac:unix {
diff --git a/src/lib/navigation/completer/locationcompleterrefreshjob.cpp b/src/lib/navigation/completer/locationcompleterrefreshjob.cpp
index 8a845ed81..762955cf5 100644
--- a/src/lib/navigation/completer/locationcompleterrefreshjob.cpp
+++ b/src/lib/navigation/completer/locationcompleterrefreshjob.cpp
@@ -28,11 +28,7 @@
 
 #include <QDateTime>
 
-#if QT_VERSION >= 0x050000
 #include <QtConcurrent/QtConcurrentRun>
-#else
-#include <QtConcurrentRun>
-#endif
 
 LocationCompleterRefreshJob::LocationCompleterRefreshJob(const QString &searchString)
     : QObject()
diff --git a/src/lib/network/schemehandlers/adblockschemehandler.cpp b/src/lib/network/schemehandlers/adblockschemehandler.cpp
index e339d7c35..5a45db66b 100644
--- a/src/lib/network/schemehandlers/adblockschemehandler.cpp
+++ b/src/lib/network/schemehandlers/adblockschemehandler.cpp
@@ -22,9 +22,7 @@
 #include <QNetworkRequest>
 #include <QMessageBox>
 
-#if QT_VERSION >= 0x050000
 #include <QUrlQuery>
-#endif
 
 AdBlockSchemeHandler::AdBlockSchemeHandler()
     : SchemeHandler()
@@ -40,12 +38,7 @@ QNetworkReply* AdBlockSchemeHandler::createRequest(QNetworkAccessManager::Operat
     }
 
     const QUrl url = request.url();
-    const QList<QPair<QString, QString> > queryItems =
-#if QT_VERSION >= 0x050000
-        QUrlQuery(url).queryItems();
-#else
-        url.queryItems();
-#endif
+    const QList<QPair<QString, QString> > queryItems = QUrlQuery(url).queryItems();
 
     QString subscriptionTitle;
     QString subscriptionUrl;
diff --git a/src/lib/network/schemehandlers/qupzillaschemehandler.cpp b/src/lib/network/schemehandlers/qupzillaschemehandler.cpp
index 7ddb372d2..360b300c7 100644
--- a/src/lib/network/schemehandlers/qupzillaschemehandler.cpp
+++ b/src/lib/network/schemehandlers/qupzillaschemehandler.cpp
@@ -35,11 +35,7 @@
 #include <QSettings>
 #include <QWebSecurityOrigin>
 
-#if QT_VERSION < 0x050000
-#include "qwebkitversion.h"
-#else
 #include <QWebEnginePage>
-#endif
 
 static QString authorString(const char* name, const QString &mail)
 {
diff --git a/src/lib/opensearch/opensearchengine.cpp b/src/lib/opensearch/opensearchengine.cpp
index 030e4ac94..c73d840b3 100644
--- a/src/lib/opensearch/opensearchengine.cpp
+++ b/src/lib/opensearch/opensearchengine.cpp
@@ -47,9 +47,7 @@
 #include <qregexp.h>
 #include <qstringlist.h>
 
-#if QT_VERSION >= 0x050000
 #include <QUrlQuery>
-#endif
 
 
 /*!
@@ -226,22 +224,14 @@ QUrl OpenSearchEngine::searchUrl(const QString &searchTerm) const
 
     QUrl retVal = QUrl::fromEncoded(parseTemplate(searchTerm, m_searchUrlTemplate).toUtf8());
 
-#if QT_VERSION >= 0x050000
     QUrlQuery query(retVal);
-#endif
     if (m_searchMethod != QLatin1String("post")) {
         Parameters::const_iterator end = m_searchParameters.constEnd();
         Parameters::const_iterator i = m_searchParameters.constBegin();
         for (; i != end; ++i) {
-#if QT_VERSION >= 0x050000
             query.addQueryItem(i->first, parseTemplate(searchTerm, i->second));
-#else
-            retVal.addQueryItem(i->first, parseTemplate(searchTerm, i->second));
-#endif
         }
-#if QT_VERSION >= 0x050000
         retVal.setQuery(query);
-#endif
     }
 
     return retVal;
@@ -255,21 +245,13 @@ QByteArray OpenSearchEngine::getPostData(const QString &searchTerm) const
 
     QUrl retVal = QUrl("http://foo.bar");
 
-#if QT_VERSION >= 0x050000
     QUrlQuery query(retVal);
-#endif
     Parameters::const_iterator end = m_searchParameters.constEnd();
     Parameters::const_iterator i = m_searchParameters.constBegin();
     for (; i != end; ++i) {
-#if QT_VERSION >= 0x050000
         query.addQueryItem(i->first, parseTemplate(searchTerm, i->second));
-#else
-        retVal.addQueryItem(i->first, parseTemplate(searchTerm, i->second));
-#endif
     }
-#if QT_VERSION >= 0x050000
     retVal.setQuery(query);
-#endif
 
     QByteArray data = retVal.toEncoded(QUrl::RemoveScheme);
     return data.contains('?') ? data.mid(data.lastIndexOf('?') + 1) : QByteArray();
@@ -324,22 +306,14 @@ QUrl OpenSearchEngine::suggestionsUrl(const QString &searchTerm) const
 
     QUrl retVal = QUrl::fromEncoded(parseTemplate(searchTerm, m_suggestionsUrlTemplate).toUtf8());
 
-#if QT_VERSION >= 0x050000
     QUrlQuery query(retVal);
-#endif
     if (m_suggestionsMethod != QLatin1String("post")) {
         Parameters::const_iterator end = m_suggestionsParameters.constEnd();
         Parameters::const_iterator i = m_suggestionsParameters.constBegin();
         for (; i != end; ++i) {
-#if QT_VERSION >= 0x050000
             query.addQueryItem(i->first, parseTemplate(searchTerm, i->second));
-#else
-            retVal.addQueryItem(i->first, parseTemplate(searchTerm, i->second));
-#endif
         }
-#if QT_VERSION >= 0x050000
         retVal.setQuery(query);
-#endif
     }
 
     return retVal;
diff --git a/src/lib/opensearch/searchenginesmanager.cpp b/src/lib/opensearch/searchenginesmanager.cpp
index 7725cba1e..42e84436e 100644
--- a/src/lib/opensearch/searchenginesmanager.cpp
+++ b/src/lib/opensearch/searchenginesmanager.cpp
@@ -32,9 +32,7 @@
 #include <QSqlQuery>
 #include <QBuffer>
 
-#if QT_VERSION >= 0x050000
 #include <QUrlQuery>
-#endif
 
 #define ENSURE_LOADED if (!m_settingsLoaded) loadSettings();
 
@@ -290,7 +288,6 @@ void SearchEnginesManager::addEngineFromForm(const QWebElement &element, WebView
         parameterUrl = QUrl("http://foo.bar");
     }
 
-#if QT_VERSION >= 0x050000
     QUrlQuery query(parameterUrl);
     query.addQueryItem(element.attribute("name"), "%s");
 
@@ -304,28 +301,6 @@ void SearchEnginesManager::addEngineFromForm(const QWebElement &element, WebView
     }
 
     parameterUrl.setQuery(query);
-#else
-    QList<QPair<QByteArray, QByteArray> > queryItems;
-
-    QPair<QByteArray, QByteArray> item;
-    item.first = element.attribute("name").toUtf8();
-    item.second = "%s";
-    queryItems.append(item);
-
-    QWebElementCollection allInputs = formElement.findAll("input");
-    foreach (QWebElement e, allInputs) {
-        if (element == e || !e.hasAttribute("name")) {
-            continue;
-        }
-
-        QPair<QByteArray, QByteArray> item;
-        item.first = QUrl::toPercentEncoding(e.attribute("name").toUtf8());
-        item.second = QUrl::toPercentEncoding(e.evaluateJavaScript("this.value").toByteArray());
-
-        queryItems.append(item);
-    }
-    parameterUrl.setEncodedQueryItems(parameterUrl.encodedQueryItems() + queryItems);
-#endif
 
     if (!isPost) {
         actionUrl = parameterUrl;
diff --git a/src/lib/other/aboutdialog.cpp b/src/lib/other/aboutdialog.cpp
index 86a553d4b..cac7625a3 100644
--- a/src/lib/other/aboutdialog.cpp
+++ b/src/lib/other/aboutdialog.cpp
@@ -23,11 +23,7 @@
 #include "webpage.h"
 #include "qtwin.h"
 
-#if QT_VERSION < 0x050000
-#include "qwebkitversion.h"
-#else
 #include <QWebEnginePage>
-#endif
 
 AboutDialog::AboutDialog(QWidget* parent)
     : QDialog(parent),
diff --git a/src/lib/other/pagescreen.cpp b/src/lib/other/pagescreen.cpp
index f833f6e48..6af8f8e50 100644
--- a/src/lib/other/pagescreen.cpp
+++ b/src/lib/other/pagescreen.cpp
@@ -35,11 +35,7 @@
 #include <QCloseEvent>
 #include <QPrinter>
 
-#if QT_VERSION >= 0x050000
 #include <QtConcurrent/QtConcurrentRun>
-#else
-#include <QtConcurrentRun>
-#endif
 
 PageScreen::PageScreen(WebView* view, QWidget* parent)
     : QDialog(parent)
diff --git a/src/lib/tools/certificateinfowidget.cpp b/src/lib/tools/certificateinfowidget.cpp
index aff104dae..f4dd878f9 100644
--- a/src/lib/tools/certificateinfowidget.cpp
+++ b/src/lib/tools/certificateinfowidget.cpp
@@ -25,13 +25,8 @@
 
 QString CertificateInfoWidget::certificateItemText(const QSslCertificate &cert)
 {
-#if QT_VERSION >= 0x050000
     QString commonName = cert.subjectInfo(QSslCertificate::CommonName).isEmpty() ? QString() : cert.subjectInfo(QSslCertificate::CommonName).at(0);
     QString organization = cert.subjectInfo(QSslCertificate::Organization).isEmpty() ? QString() : cert.subjectInfo(QSslCertificate::Organization).at(0);
-#else
-    QString commonName = cert.subjectInfo(QSslCertificate::CommonName);
-    QString organization = cert.subjectInfo(QSslCertificate::Organization);
-#endif
 
     if (commonName.isEmpty()) {
         return clearCertSpecialSymbols(organization);
diff --git a/src/lib/tools/headerview.cpp b/src/lib/tools/headerview.cpp
index 813d058dd..73bb49c47 100644
--- a/src/lib/tools/headerview.cpp
+++ b/src/lib/tools/headerview.cpp
@@ -26,11 +26,7 @@ HeaderView::HeaderView(QAbstractItemView* parent)
     , m_menu(0)
     , m_resizeOnShow(false)
 {
-#if QT_VERSION >= 0x050000
     setSectionsMovable(true);
-#else
-    setMovable(true);
-#endif
     setStretchLastSection(true);
     setDefaultAlignment(Qt::AlignLeft);
     setMinimumSectionSize(60);
diff --git a/src/lib/tools/qzregexp.cpp b/src/lib/tools/qzregexp.cpp
index fe8caf92f..40adcc5cb 100644
--- a/src/lib/tools/qzregexp.cpp
+++ b/src/lib/tools/qzregexp.cpp
@@ -18,7 +18,6 @@
 #include "qzregexp.h"
 #include "qztools.h"
 
-#if (QT_VERSION >= 0x050000)
 QzRegExp::QzRegExp()
     : QRegularExpression(QString(), QRegularExpression::DotMatchesEverythingOption)
     , m_matchedLength(-1)
@@ -83,5 +82,4 @@ QString QzRegExp::cap(int nth) const
 
     return m_capturedTexts.at(nth);
 }
-#endif // (QT_VERSION >= 0x050000)
 
diff --git a/src/lib/tools/qzregexp.h b/src/lib/tools/qzregexp.h
index ce05b227d..8c276d5d8 100644
--- a/src/lib/tools/qzregexp.h
+++ b/src/lib/tools/qzregexp.h
@@ -18,13 +18,6 @@
 #ifndef QZREGEXP_H
 #define QZREGEXP_H
 
-#include <QObject> // Needed for QT_VERSION
-
-#if (QT_VERSION < 0x050000)
-// Qt 4 - use QRegExp directly
-#include <QRegExp>
-#define QzRegExp QRegExp
-#else // Qt 5
 #include <QRegularExpression>
 #include <QStringList>
 
@@ -47,6 +40,5 @@ private:
     int m_matchedLength;
 
 };
-#endif // Qt 5
 
 #endif // QZREGEXP_H
diff --git a/src/lib/tools/sqldatabase.cpp b/src/lib/tools/sqldatabase.cpp
index 10f94b440..b37dd38c9 100644
--- a/src/lib/tools/sqldatabase.cpp
+++ b/src/lib/tools/sqldatabase.cpp
@@ -20,11 +20,7 @@
 #include <QThread>
 #include <QMutexLocker>
 
-#if QT_VERSION >= 0x050000
 #include <QtConcurrent/QtConcurrentRun>
-#else
-#include <QtConcurrentRun>
-#endif
 
 Q_GLOBAL_STATIC(SqlDatabase, qz_sql_database)
 
diff --git a/src/main/main.cpp b/src/main/main.cpp
index bad4c0195..566a30240 100644
--- a/src/main/main.cpp
+++ b/src/main/main.cpp
@@ -29,14 +29,7 @@
 #include <QDir>
 #include <QDateTime>
 #include <QTextStream>
-
-#if QT_VERSION >= 0x050000
 #include <QWebEnginePage>
-#else
-#include "qwebkitversion.h"
-#endif
-
-#include <qtwebengineglobal.h>
 
 void qupzilla_signal_handler(int s)
 {
@@ -107,30 +100,6 @@ void qupzilla_signal_handler(int s)
 #endif // defined(Q_OS_LINUX) || defined(__GLIBC__) || defined(__FreeBSD__)
 
 #ifndef Q_OS_WIN
-#if (QT_VERSION < 0x050000)
-void msgHandler(QtMsgType type, const char* msg)
-{
-    // Skip this debug message as it may occur in a large amount over time
-    if (strcmp("QFont::setPixelSize: Pixel size <= 0 (0)", msg) == 0) {
-        return;
-    }
-
-    switch (type) {
-    case QtDebugMsg:
-    case QtWarningMsg:
-    case QtCriticalMsg:
-        std::cerr << msg << std::endl;
-        break;
-
-    case QtFatalMsg:
-        std::cerr << "Fatal: " << msg << std::endl;
-        abort();
-
-    default:
-        break;
-    }
-}
-#else
 void msgHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
 {
     if (msg.startsWith(QL1S("QSslSocket: cannot resolve SSLv2_")))
@@ -153,24 +122,14 @@ void msgHandler(QtMsgType type, const QMessageLogContext &context, const QString
     }
 }
 #endif
-#endif
 
 int main(int argc, char* argv[])
 {
     QT_REQUIRE_VERSION(argc, argv, "4.7.0");
 
 #ifndef Q_OS_WIN
-#if (QT_VERSION < 0x050000)
-    qInstallMsgHandler(&msgHandler);
-#else
     qInstallMessageHandler(&msgHandler);
 #endif
-#endif
-
-#if defined(QZ_WS_X11) && QT_VERSION < 0x050000
-    // Better overall performance on X11
-    QApplication::setGraphicsSystem(QSL("raster"));
-#endif
 
 #if defined(Q_OS_LINUX) || defined(__GLIBC__) || defined(__FreeBSD__)
     signal(SIGSEGV, qupzilla_signal_handler);
diff --git a/src/main/main.pro b/src/main/main.pro
index 9f1905dfa..7cd3fcfc2 100644
--- a/src/main/main.pro
+++ b/src/main/main.pro
@@ -1,10 +1,6 @@
 include(../defines.pri)
 
-isEqual(QT_MAJOR_VERSION, 5) {
-    QT += webengine webenginewidgets network widgets printsupport sql script
-} else {
-    QT += core gui webkit sql network script
-}
+QT += webengine webenginewidgets network widgets printsupport sql script
 
 TARGET = qupzilla
 mac: TARGET = QupZilla
diff --git a/tests/autotests/autotests.pro b/tests/autotests/autotests.pro
index 191669371..30203e7b1 100644
--- a/tests/autotests/autotests.pro
+++ b/tests/autotests/autotests.pro
@@ -1,11 +1,6 @@
 include($$PWD/../../src/defines.pri)
 
-isEqual(QT_MAJOR_VERSION, 5) {
-    QT += webkitwidgets network widgets printsupport sql script gui-private testlib
-} else {
-    QT += core gui webkit sql network script
-    CONFIG += qtestlib
-}
+QT += webenginewidgets network widgets printsupport sql script gui-private testlib
 
 TARGET = autotests