diff --git a/src/app/application.cpp b/src/app/application.cpp
index 80b0dd61d..e02205995 100644
--- a/src/app/application.cpp
+++ b/src/app/application.cpp
@@ -141,7 +141,9 @@ Application::Application(int &argc, char **argv)
     setOrganizationDomain("qbittorrent.org");
 #if !defined(DISABLE_GUI)
     setDesktopFileName("org.qbittorrent.qBittorrent");
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
     setAttribute(Qt::AA_UseHighDpiPixmaps, true);  // opt-in to the high DPI pixmap support
+#endif
     setQuitOnLastWindowClosed(false);
     QPixmapCache::setCacheLimit(PIXMAP_CACHE_SIZE);
 #endif
diff --git a/src/app/main.cpp b/src/app/main.cpp
index 270c4e421..7406545b4 100644
--- a/src/app/main.cpp
+++ b/src/app/main.cpp
@@ -134,7 +134,7 @@ int main(int argc, char *argv[])
     // We must save it here because QApplication constructor may change it
     bool isOneArg = (argc == 2);
 
-#if !defined(DISABLE_GUI)
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0)) && !defined(DISABLE_GUI)
     // Attribute Qt::AA_EnableHighDpiScaling must be set before QCoreApplication is created
     if (qgetenv("QT_ENABLE_HIGHDPI_SCALING").isEmpty() && qgetenv("QT_AUTO_SCREEN_SCALE_FACTOR").isEmpty())
         Application::setAttribute(Qt::AA_EnableHighDpiScaling, true);
diff --git a/src/base/bittorrent/bencoderesumedatastorage.cpp b/src/base/bittorrent/bencoderesumedatastorage.cpp
index 0c6835882..668556427 100644
--- a/src/base/bittorrent/bencoderesumedatastorage.cpp
+++ b/src/base/bittorrent/bencoderesumedatastorage.cpp
@@ -35,6 +35,7 @@
 #include <libtorrent/write_resume_data.hpp>
 
 #include <QByteArray>
+#include <QDebug>
 #include <QRegularExpression>
 #include <QThread>
 
@@ -113,7 +114,7 @@ BitTorrent::BencodeResumeDataStorage::BencodeResumeDataStorage(const QString &pa
 
     loadQueue(m_resumeDataDir.absoluteFilePath(QLatin1String("queue")));
 
-    qDebug("Registered torrents count: %d", m_registeredTorrents.size());
+    qDebug() << "Registered torrents count: " << m_registeredTorrents.size();
 
     m_asyncWorker->moveToThread(m_ioThread);
     connect(m_ioThread, &QThread::finished, m_asyncWorker, &QObject::deleteLater);
diff --git a/src/base/bittorrent/session.cpp b/src/base/bittorrent/session.cpp
index 98599d0a0..7bbf3c6af 100644
--- a/src/base/bittorrent/session.cpp
+++ b/src/base/bittorrent/session.cpp
@@ -2523,7 +2523,7 @@ QStringList Session::getListeningIPs() const
     }
 
     const QList<QNetworkAddressEntry> addresses = networkIFace.addressEntries();
-    qDebug("This network interface has %d IP addresses", addresses.size());
+    qDebug() << "This network interface has " << addresses.size() << " IP addresses";
     for (const QNetworkAddressEntry &entry : addresses)
         checkAndAddIP(entry.ip(), configuredAddr);
 
diff --git a/src/gui/addnewtorrentdialog.ui b/src/gui/addnewtorrentdialog.ui
index 3d5a66e8b..992109abc 100644
--- a/src/gui/addnewtorrentdialog.ui
+++ b/src/gui/addnewtorrentdialog.ui
@@ -326,9 +326,6 @@
           </item>
           <item row="2" column="1">
            <widget class="QLabel" name="labelInfohash1Data">
-            <property name="textFormat">
-             <enum>Qt::PlainText</enum>
-            </property>
             <property name="textInteractionFlags">
              <set>Qt::TextSelectableByMouse</set>
             </property>
@@ -350,8 +347,8 @@
           </item>
           <item row="3" column="1">
            <widget class="QLabel" name="labelInfohash2Data">
-            <property name="text">
-             <string/>
+            <property name="textInteractionFlags">
+             <set>Qt::TextSelectableByMouse</set>
             </property>
            </widget>
           </item>
diff --git a/src/gui/properties/piecesbar.cpp b/src/gui/properties/piecesbar.cpp
index f1f042b92..fda9c8113 100644
--- a/src/gui/properties/piecesbar.cpp
+++ b/src/gui/properties/piecesbar.cpp
@@ -186,7 +186,7 @@ void PiecesBar::paintEvent(QPaintEvent *)
     if (!m_highlightedRegion.isNull())
     {
         QColor highlightColor {this->palette().color(QPalette::Active, QPalette::Highlight)};
-        highlightColor.setAlphaF(0.35);
+        highlightColor.setAlphaF(0.35f);
         QRect targetHighlightRect {m_highlightedRegion.adjusted(borderWidth, borderWidth, borderWidth, height() - 2 * borderWidth)};
         painter.fillRect(targetHighlightRect, highlightColor);
     }
diff --git a/src/gui/properties/propertieswidget.cpp b/src/gui/properties/propertieswidget.cpp
index 0987ca141..531447fc8 100644
--- a/src/gui/properties/propertieswidget.cpp
+++ b/src/gui/properties/propertieswidget.cpp
@@ -412,7 +412,7 @@ void PropertiesWidget::saveSettings()
         sizes = hSplitter->sizes();
     else
         sizes = m_slideSizes;
-    qDebug("Sizes: %d", sizes.size());
+
     if (sizes.size() == 2)
         pref->setPropSplitterSizes(QString::number(sizes.first()) + ',' + QString::number(sizes.last()));
     pref->setPropFileListState(m_ui->filesList->header()->saveState());
@@ -752,21 +752,31 @@ void PropertiesWidget::configure()
     // Speed widget
     if (Preferences::instance()->isSpeedWidgetEnabled())
     {
-        if (!m_speedWidget || !qobject_cast<SpeedWidget *>(m_speedWidget))
+        if (!qobject_cast<SpeedWidget *>(m_speedWidget))
         {
-            m_ui->speedLayout->removeWidget(m_speedWidget);
-            delete m_speedWidget;
-            m_speedWidget = new SpeedWidget {this};
+            if (m_speedWidget)
+            {
+                m_ui->speedLayout->removeWidget(m_speedWidget);
+                delete m_speedWidget;
+            }
+
+            m_speedWidget = new SpeedWidget(this);
             m_ui->speedLayout->addWidget(m_speedWidget);
         }
     }
     else
     {
-        if (!m_speedWidget || !qobject_cast<QLabel *>(m_speedWidget))
+        if (!qobject_cast<QLabel *>(m_speedWidget))
         {
-            m_ui->speedLayout->removeWidget(m_speedWidget);
-            delete m_speedWidget;
-            auto *label = new QLabel(tr("<center><b>Speed graphs are disabled</b><p>You may change this setting in Advanced Options </center>"), this);
+            if (m_speedWidget)
+            {
+                m_ui->speedLayout->removeWidget(m_speedWidget);
+                delete m_speedWidget;
+            }
+
+            const auto displayText = QString::fromLatin1("<center><b>%1</b><p>%2</p></center>")
+                .arg(tr("Speed graphs are disabled"), tr("You can enable it in Advanced Options"));
+            auto *label = new QLabel(displayText, this);
             label->setAlignment(Qt::AlignHCenter | Qt::AlignVCenter);
             m_speedWidget = label;
             m_ui->speedLayout->addWidget(m_speedWidget);
diff --git a/src/src.pro b/src/src.pro
index 1ba2f49fc..2728e6d5f 100644
--- a/src/src.pro
+++ b/src/src.pro
@@ -23,7 +23,7 @@ nogui {
         DEFINES += QBT_STATIC_QT
         QTPLUGIN += qico
     }
-    win32: lessThan(QT_VERSION_MAJOR, 6) {
+    win32: lessThan(QT_MAJOR_VERSION, 6) {
         QT += winextras
     }
     macx {