diff --git a/src/app/stacktrace.h b/src/app/stacktrace.h
index 5ba3c5d43..1b332ecf5 100644
--- a/src/app/stacktrace.h
+++ b/src/app/stacktrace.h
@@ -12,7 +12,7 @@
 #include <vector>
 
 /** Print a demangled stack backtrace of the caller function to FILE* out. */
-static inline void print_stacktrace(FILE *out = stderr, unsigned int max_frames = 63)
+static inline void print_stacktrace(FILE *out = stderr, const int max_frames = 63)
 {
     fprintf(out, "Stack trace:\n");
 
diff --git a/src/base/bittorrent/cachestatus.h b/src/base/bittorrent/cachestatus.h
index 5f59ba21c..4dd228dda 100644
--- a/src/base/bittorrent/cachestatus.h
+++ b/src/base/bittorrent/cachestatus.h
@@ -34,10 +34,10 @@ namespace BitTorrent
 {
     struct CacheStatus
     {
-        quint64 totalUsedBuffers = 0;
-        quint64 jobQueueLength = 0;
-        quint64 averageJobTime = 0;
-        quint64 queuedBytes = 0;
+        qint64 totalUsedBuffers = 0;
+        qint64 jobQueueLength = 0;
+        qint64 averageJobTime = 0;
+        qint64 queuedBytes = 0;
         qreal readRatio = 0;  // TODO: remove when LIBTORRENT_VERSION_NUM >= 20000
     };
 }
diff --git a/src/base/bittorrent/session.cpp b/src/base/bittorrent/session.cpp
index 48996599e..22aa0c69d 100644
--- a/src/base/bittorrent/session.cpp
+++ b/src/base/bittorrent/session.cpp
@@ -4702,12 +4702,12 @@ void Session::startUpTorrents()
     }
 }
 
-quint64 Session::getAlltimeDL() const
+qint64 Session::getAlltimeDL() const
 {
     return m_statistics->getAlltimeDL();
 }
 
-quint64 Session::getAlltimeUL() const
+qint64 Session::getAlltimeUL() const
 {
     return m_statistics->getAlltimeUL();
 }
@@ -5201,10 +5201,10 @@ void Session::handleSessionStatsAlert(const lt::session_stats_alert *p)
     const int64_t dhtDownload = stats[m_metricIndices.dht.dhtBytesIn];
     const int64_t dhtUpload = stats[m_metricIndices.dht.dhtBytesOut];
 
-    auto calcRate = [interval](const quint64 previous, const quint64 current)
+    const auto calcRate = [interval](const qint64 previous, const qint64 current) -> qint64
     {
         Q_ASSERT(current >= previous);
-        return static_cast<quint64>((current - previous) / interval);
+        return ((current - previous) / interval);
     };
 
     m_status.payloadDownloadRate = calcRate(m_status.totalPayloadDownload, totalPayloadDownload);
diff --git a/src/base/bittorrent/session.h b/src/base/bittorrent/session.h
index c7c9e6fb3..7f8a99033 100644
--- a/src/base/bittorrent/session.h
+++ b/src/base/bittorrent/session.h
@@ -469,8 +469,8 @@ namespace BitTorrent
         bool hasRunningSeed() const;
         const SessionStatus &status() const;
         const CacheStatus &cacheStatus() const;
-        quint64 getAlltimeDL() const;
-        quint64 getAlltimeUL() const;
+        qint64 getAlltimeDL() const;
+        qint64 getAlltimeUL() const;
         bool isListening() const;
 
         MaxRatioAction maxRatioAction() const;
diff --git a/src/base/bittorrent/sessionstatus.h b/src/base/bittorrent/sessionstatus.h
index 0f8ba5caf..58aee588b 100644
--- a/src/base/bittorrent/sessionstatus.h
+++ b/src/base/bittorrent/sessionstatus.h
@@ -39,37 +39,37 @@ namespace BitTorrent
         // Current download rate for the BT
         // session. Payload means that it only take into
         // account "useful" part of the rate
-        quint64 payloadDownloadRate = 0;
+        qint64 payloadDownloadRate = 0;
 
         // Current upload rate for the BT
         // session. Payload means that it only take into
         // account "useful" part of the rate
-        quint64 payloadUploadRate = 0;
+        qint64 payloadUploadRate = 0;
 
         // Additional download/upload rates
-        quint64 uploadRate = 0;
-        quint64 downloadRate = 0;
-        quint64 ipOverheadUploadRate = 0;
-        quint64 ipOverheadDownloadRate = 0;
-        quint64 dhtUploadRate = 0;
-        quint64 dhtDownloadRate = 0;
-        quint64 trackerUploadRate = 0;
-        quint64 trackerDownloadRate = 0;
+        qint64 uploadRate = 0;
+        qint64 downloadRate = 0;
+        qint64 ipOverheadUploadRate = 0;
+        qint64 ipOverheadDownloadRate = 0;
+        qint64 dhtUploadRate = 0;
+        qint64 dhtDownloadRate = 0;
+        qint64 trackerUploadRate = 0;
+        qint64 trackerDownloadRate = 0;
 
-        quint64 totalDownload = 0;
-        quint64 totalUpload = 0;
-        quint64 totalPayloadDownload = 0;
-        quint64 totalPayloadUpload = 0;
-        quint64 ipOverheadUpload = 0;
-        quint64 ipOverheadDownload = 0;
-        quint64 dhtUpload = 0;
-        quint64 dhtDownload = 0;
-        quint64 trackerUpload = 0;
-        quint64 trackerDownload = 0;
-        quint64 totalWasted = 0;
-        quint64 diskReadQueue = 0;
-        quint64 diskWriteQueue = 0;
-        quint64 dhtNodes = 0;
-        quint64 peersCount = 0;
+        qint64 totalDownload = 0;
+        qint64 totalUpload = 0;
+        qint64 totalPayloadDownload = 0;
+        qint64 totalPayloadUpload = 0;
+        qint64 ipOverheadUpload = 0;
+        qint64 ipOverheadDownload = 0;
+        qint64 dhtUpload = 0;
+        qint64 dhtDownload = 0;
+        qint64 trackerUpload = 0;
+        qint64 trackerDownload = 0;
+        qint64 totalWasted = 0;
+        qint64 diskReadQueue = 0;
+        qint64 diskWriteQueue = 0;
+        qint64 dhtNodes = 0;
+        qint64 peersCount = 0;
     };
 }
diff --git a/src/base/bittorrent/statistics.cpp b/src/base/bittorrent/statistics.cpp
index 55d978d70..0af93c9c4 100644
--- a/src/base/bittorrent/statistics.cpp
+++ b/src/base/bittorrent/statistics.cpp
@@ -42,10 +42,6 @@ using namespace BitTorrent;
 Statistics::Statistics(Session *session)
     : QObject(session)
     , m_session(session)
-    , m_sessionUL(0)
-    , m_sessionDL(0)
-    , m_lastWrite(0)
-    , m_dirty(false)
 {
     load();
     connect(&m_timer, &QTimer::timeout, this, &Statistics::gather);
@@ -59,12 +55,12 @@ Statistics::~Statistics()
     save();
 }
 
-quint64 Statistics::getAlltimeDL() const
+qint64 Statistics::getAlltimeDL() const
 {
     return m_alltimeDL + m_sessionDL;
 }
 
-quint64 Statistics::getAlltimeUL() const
+qint64 Statistics::getAlltimeUL() const
 {
     return m_alltimeUL + m_sessionUL;
 }
@@ -95,8 +91,8 @@ void Statistics::save() const
 
     SettingsPtr s = Profile::instance()->applicationSettings(u"qBittorrent-data"_qs);
     QVariantHash v;
-    v.insert(u"AlltimeDL"_qs, m_alltimeDL + m_sessionDL);
-    v.insert(u"AlltimeUL"_qs, m_alltimeUL + m_sessionUL);
+    v.insert(u"AlltimeDL"_qs, (m_alltimeDL + m_sessionDL));
+    v.insert(u"AlltimeUL"_qs, (m_alltimeUL + m_sessionUL));
     s->setValue(u"Stats/AllStats"_qs, v);
     m_dirty = false;
     m_lastWrite = now;
diff --git a/src/base/bittorrent/statistics.h b/src/base/bittorrent/statistics.h
index 5704b1922..0d045ecec 100644
--- a/src/base/bittorrent/statistics.h
+++ b/src/base/bittorrent/statistics.h
@@ -45,8 +45,8 @@ public:
     explicit Statistics(BitTorrent::Session *session);
     ~Statistics();
 
-    quint64 getAlltimeDL() const;
-    quint64 getAlltimeUL() const;
+    qint64 getAlltimeDL() const;
+    qint64 getAlltimeUL() const;
 
 private slots:
     void gather();
@@ -56,13 +56,12 @@ private:
     void load();
 
     BitTorrent::Session *m_session;
-    // Will overflow at 15.9 EiB
-    quint64 m_alltimeUL;
-    quint64 m_alltimeDL;
-    quint64 m_sessionUL;
-    quint64 m_sessionDL;
-    mutable qint64 m_lastWrite;
-    mutable bool m_dirty;
+    qint64 m_alltimeUL = 0;
+    qint64 m_alltimeDL = 0;
+    qint64 m_sessionUL = 0;
+    qint64 m_sessionDL = 0;
+    mutable qint64 m_lastWrite = 0;
+    mutable bool m_dirty = false;
 
     QTimer m_timer;
 };
diff --git a/src/base/search/searchpluginmanager.h b/src/base/search/searchpluginmanager.h
index 0257313d3..8b4a0efd1 100644
--- a/src/base/search/searchpluginmanager.h
+++ b/src/base/search/searchpluginmanager.h
@@ -36,7 +36,7 @@
 #include "base/path.h"
 #include "base/utils/version.h"
 
-using PluginVersion = Utils::Version<unsigned short, 2>;
+using PluginVersion = Utils::Version<short, 2>;
 Q_DECLARE_METATYPE(PluginVersion)
 
 namespace Net
diff --git a/src/gui/optionsdialog.cpp b/src/gui/optionsdialog.cpp
index ee6785429..2ae72ddf3 100644
--- a/src/gui/optionsdialog.cpp
+++ b/src/gui/optionsdialog.cpp
@@ -1638,7 +1638,7 @@ void OptionsDialog::setLocale(const QString &localeStr)
     if (index < 0)
     {
         // Unrecognized, use US English
-        index = m_ui->comboI18n->findData(u"en", Qt::UserRole);
+        index = m_ui->comboI18n->findData(u"en"_qs, Qt::UserRole);
         Q_ASSERT(index >= 0);
     }
     m_ui->comboI18n->setCurrentIndex(index);
diff --git a/src/gui/rss/articlelistwidget.cpp b/src/gui/rss/articlelistwidget.cpp
index 64d32635c..031c59383 100644
--- a/src/gui/rss/articlelistwidget.cpp
+++ b/src/gui/rss/articlelistwidget.cpp
@@ -47,7 +47,7 @@ ArticleListWidget::ArticleListWidget(QWidget *parent)
 RSS::Article *ArticleListWidget::getRSSArticle(QListWidgetItem *item) const
 {
     Q_ASSERT(item);
-    return reinterpret_cast<RSS::Article *>(item->data(Qt::UserRole).value<quintptr>());
+    return item->data(Qt::UserRole).value<RSS::Article *>();
 }
 
 QListWidgetItem *ArticleListWidget::mapRSSArticle(RSS::Article *rssArticle) const
@@ -127,7 +127,7 @@ QListWidgetItem *ArticleListWidget::createItem(RSS::Article *article) const
     auto *item = new QListWidgetItem;
 
     item->setData(Qt::DisplayRole, article->title());
-    item->setData(Qt::UserRole, reinterpret_cast<quintptr>(article));
+    item->setData(Qt::UserRole, QVariant::fromValue(article));
     if (article->isRead())
     {
         const QColor defaultColor {palette().color(QPalette::Inactive, QPalette::WindowText)};
diff --git a/src/gui/rss/feedlistwidget.cpp b/src/gui/rss/feedlistwidget.cpp
index 681fc840a..92cacd4d1 100644
--- a/src/gui/rss/feedlistwidget.cpp
+++ b/src/gui/rss/feedlistwidget.cpp
@@ -105,7 +105,7 @@ FeedListWidget::FeedListWidget(QWidget *parent)
     m_rssToTreeItemMapping[RSS::Session::instance()->rootFolder()] = invisibleRootItem();
 
     m_unreadStickyItem = new FeedListItem(this);
-    m_unreadStickyItem->setData(0, Qt::UserRole, reinterpret_cast<quintptr>(RSS::Session::instance()->rootFolder()));
+    m_unreadStickyItem->setData(0, Qt::UserRole, QVariant::fromValue(RSS::Session::instance()->rootFolder()));
     m_unreadStickyItem->setText(0, tr("Unread  (%1)").arg(RSS::Session::instance()->rootFolder()->unreadCount()));
     m_unreadStickyItem->setData(0, Qt::DecorationRole, UIThemeManager::instance()->getIcon(u"mail-folder-inbox"_qs));
     m_unreadStickyItem->setData(0, StickyItemTagRole, true);
@@ -213,7 +213,7 @@ RSS::Item *FeedListWidget::getRSSItem(QTreeWidgetItem *item) const
 {
     if (!item) return nullptr;
 
-    return reinterpret_cast<RSS::Item *>(item->data(0, Qt::UserRole).value<quintptr>());
+    return item->data(0, Qt::UserRole).value<RSS::Item *>();
 }
 
 QTreeWidgetItem *FeedListWidget::mapRSSItem(RSS::Item *rssItem) const
@@ -275,7 +275,7 @@ QTreeWidgetItem *FeedListWidget::createItem(RSS::Item *rssItem, QTreeWidgetItem
 {
     auto *item = new FeedListItem;
     item->setData(0, Qt::DisplayRole, u"%1  (%2)"_qs.arg(rssItem->name(), QString::number(rssItem->unreadCount())));
-    item->setData(0, Qt::UserRole, reinterpret_cast<quintptr>(rssItem));
+    item->setData(0, Qt::UserRole, QVariant::fromValue(rssItem));
     m_rssToTreeItemMapping[rssItem] = item;
 
     QIcon icon;
diff --git a/src/gui/rss/rsswidget.cpp b/src/gui/rss/rsswidget.cpp
index b1d637ccf..13dd7880f 100644
--- a/src/gui/rss/rsswidget.cpp
+++ b/src/gui/rss/rsswidget.cpp
@@ -198,7 +198,7 @@ void RSSWidget::displayItemsListMenu()
     bool hasLink = false;
     for (const QListWidgetItem *item : asConst(m_articleListWidget->selectedItems()))
     {
-        auto article = reinterpret_cast<RSS::Article *>(item->data(Qt::UserRole).value<quintptr>());
+        auto article = item->data(Qt::UserRole).value<RSS::Article *>();
         Q_ASSERT(article);
 
         if (!article->torrentUrl().isEmpty())
@@ -359,7 +359,7 @@ void RSSWidget::downloadSelectedTorrents()
 {
     for (QListWidgetItem *item : asConst(m_articleListWidget->selectedItems()))
     {
-        auto article = reinterpret_cast<RSS::Article *>(item->data(Qt::UserRole).value<quintptr>());
+        auto article = item->data(Qt::UserRole).value<RSS::Article *>();
         Q_ASSERT(article);
 
         // Mark as read
@@ -380,7 +380,7 @@ void RSSWidget::openSelectedArticlesUrls()
 {
     for (QListWidgetItem *item : asConst(m_articleListWidget->selectedItems()))
     {
-        auto article = reinterpret_cast<RSS::Article *>(item->data(Qt::UserRole).value<quintptr>());
+        auto article = item->data(Qt::UserRole).value<RSS::Article *>();
         Q_ASSERT(article);
 
         // Mark as read
diff --git a/src/gui/statsdialog.cpp b/src/gui/statsdialog.cpp
index a6dd64c24..2533f98d6 100644
--- a/src/gui/statsdialog.cpp
+++ b/src/gui/statsdialog.cpp
@@ -76,8 +76,8 @@ void StatsDialog::update()
     const BitTorrent::CacheStatus &cs = BitTorrent::Session::instance()->cacheStatus();
 
     // All-time DL/UL
-    quint64 atd = BitTorrent::Session::instance()->getAlltimeDL();
-    quint64 atu = BitTorrent::Session::instance()->getAlltimeUL();
+    const qint64 atd = BitTorrent::Session::instance()->getAlltimeDL();
+    const qint64 atu = BitTorrent::Session::instance()->getAlltimeUL();
     m_ui->labelAlltimeDL->setText(Utils::Misc::friendlyUnit(atd));
     m_ui->labelAlltimeUL->setText(Utils::Misc::friendlyUnit(atu));
     // Total waste (this session)
diff --git a/src/webui/api/synccontroller.cpp b/src/webui/api/synccontroller.cpp
index 80686bb17..1c1c919e6 100644
--- a/src/webui/api/synccontroller.cpp
+++ b/src/webui/api/synccontroller.cpp
@@ -126,8 +126,8 @@ namespace
         map[KEY_TRANSFER_DLRATELIMIT] = session->downloadSpeedLimit();
         map[KEY_TRANSFER_UPRATELIMIT] = session->uploadSpeedLimit();
 
-        const quint64 atd = session->getAlltimeDL();
-        const quint64 atu = session->getAlltimeUL();
+        const qint64 atd = session->getAlltimeDL();
+        const qint64 atu = session->getAlltimeUL();
         map[KEY_TRANSFER_ALLTIME_DL] = atd;
         map[KEY_TRANSFER_ALLTIME_UL] = atu;
         map[KEY_TRANSFER_TOTAL_WASTE_SESSION] = sessionStatus.totalWasted;