diff --git a/src/cli/AddGroup.h b/src/cli/AddGroup.h
index 9976d5894..7992f16bf 100644
--- a/src/cli/AddGroup.h
+++ b/src/cli/AddGroup.h
@@ -24,9 +24,9 @@ class AddGroup : public DatabaseCommand
 {
 public:
     AddGroup();
-    ~AddGroup();
+    ~AddGroup() override;
 
-    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser);
+    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser) override;
 };
 
 #endif // KEEPASSXC_ADDGROUP_H
diff --git a/src/cli/Info.h b/src/cli/Info.h
index 1961a7b5f..386dc62eb 100644
--- a/src/cli/Info.h
+++ b/src/cli/Info.h
@@ -25,7 +25,7 @@ class Info : public DatabaseCommand
 public:
     Info();
 
-    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser);
+    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser) override;
 };
 
 #endif // KEEPASSXC_INFO_H
diff --git a/src/cli/Move.h b/src/cli/Move.h
index c506085a5..e87b0c795 100644
--- a/src/cli/Move.h
+++ b/src/cli/Move.h
@@ -24,9 +24,9 @@ class Move : public DatabaseCommand
 {
 public:
     Move();
-    ~Move();
+    ~Move() override;
 
-    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser);
+    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser) override;
 };
 
 #endif // KEEPASSXC_MOVE_H
diff --git a/src/cli/Remove.h b/src/cli/Remove.h
index 6019bfa16..640e94ea3 100644
--- a/src/cli/Remove.h
+++ b/src/cli/Remove.h
@@ -25,7 +25,7 @@ class Remove : public DatabaseCommand
 public:
     Remove();
 
-    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser);
+    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser) override;
 };
 
 #endif // KEEPASSXC_REMOVE_H
diff --git a/src/cli/RemoveGroup.h b/src/cli/RemoveGroup.h
index 2b5194665..20518a005 100644
--- a/src/cli/RemoveGroup.h
+++ b/src/cli/RemoveGroup.h
@@ -24,9 +24,9 @@ class RemoveGroup : public DatabaseCommand
 {
 public:
     RemoveGroup();
-    ~RemoveGroup();
+    ~RemoveGroup() override;
 
-    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser);
+    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser) override;
 };
 
 #endif // KEEPASSXC_REMOVEGROUP_H
diff --git a/src/cli/Show.h b/src/cli/Show.h
index 93713dbd8..98f8b3cbc 100644
--- a/src/cli/Show.h
+++ b/src/cli/Show.h
@@ -25,7 +25,7 @@ class Show : public DatabaseCommand
 public:
     Show();
 
-    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser);
+    int executeWithDatabase(QSharedPointer<Database> db, QSharedPointer<QCommandLineParser> parser) override;
 
     static const QCommandLineOption TotpOption;
     static const QCommandLineOption AttributesOption;
diff --git a/src/core/Entry.h b/src/core/Entry.h
index 6984a9845..79390ff7a 100644
--- a/src/core/Entry.h
+++ b/src/core/Entry.h
@@ -79,7 +79,7 @@ class Entry : public ModifiableObject
 
 public:
     Entry();
-    ~Entry();
+    ~Entry() override;
     const QUuid& uuid() const;
     const QString uuidToHex() const;
     int iconNumber() const;
diff --git a/src/core/EntryAttachments.h b/src/core/EntryAttachments.h
index 1fc35df89..c07c9cbf7 100644
--- a/src/core/EntryAttachments.h
+++ b/src/core/EntryAttachments.h
@@ -34,7 +34,7 @@ class EntryAttachments : public ModifiableObject
 
 public:
     explicit EntryAttachments(QObject* parent = nullptr);
-    virtual ~EntryAttachments();
+    ~EntryAttachments() override;
     QList<QString> keys() const;
     bool hasKey(const QString& key) const;
     QSet<QByteArray> values() const;
diff --git a/src/core/Group.h b/src/core/Group.h
index 748437ab1..4d1ddfd83 100644
--- a/src/core/Group.h
+++ b/src/core/Group.h
@@ -78,7 +78,7 @@ public:
     };
 
     Group();
-    ~Group();
+    ~Group() override;
 
     const QUuid& uuid() const;
     const QString uuidToHex() const;
diff --git a/src/core/InactivityTimer.h b/src/core/InactivityTimer.h
index b9de80fb4..8bde9751f 100644
--- a/src/core/InactivityTimer.h
+++ b/src/core/InactivityTimer.h
@@ -37,7 +37,7 @@ signals:
     void inactivityDetected();
 
 protected:
-    bool eventFilter(QObject* watched, QEvent* event);
+    bool eventFilter(QObject* watched, QEvent* event) override;
 
 private slots:
     void timeout();
diff --git a/src/gui/AboutDialog.h b/src/gui/AboutDialog.h
index 9ea0dc802..645fcef92 100644
--- a/src/gui/AboutDialog.h
+++ b/src/gui/AboutDialog.h
@@ -32,7 +32,7 @@ class AboutDialog : public QDialog
 
 public:
     explicit AboutDialog(QWidget* parent = nullptr);
-    ~AboutDialog();
+    ~AboutDialog() override;
 
 protected slots:
     void copyToClipboard();
diff --git a/src/gui/ApplicationSettingsWidget.h b/src/gui/ApplicationSettingsWidget.h
index 15fc5a344..e7acb37b7 100644
--- a/src/gui/ApplicationSettingsWidget.h
+++ b/src/gui/ApplicationSettingsWidget.h
@@ -46,7 +46,7 @@ class ApplicationSettingsWidget : public EditWidget
 
 public:
     explicit ApplicationSettingsWidget(QWidget* parent = nullptr);
-    ~ApplicationSettingsWidget();
+    ~ApplicationSettingsWidget() override;
     void addSettingsPage(ISettingsPage* page);
     void loadSettings();
 
diff --git a/src/gui/CategoryListWidget.h b/src/gui/CategoryListWidget.h
index cbf0ef0eb..aa182fa48 100644
--- a/src/gui/CategoryListWidget.h
+++ b/src/gui/CategoryListWidget.h
@@ -35,7 +35,7 @@ class CategoryListWidget : public QWidget
 
 public:
     CategoryListWidget(QWidget* parent = nullptr);
-    ~CategoryListWidget();
+    ~CategoryListWidget() override;
 
     int currentCategory();
     void setCurrentCategory(int index);
diff --git a/src/gui/CloneDialog.h b/src/gui/CloneDialog.h
index 8da584c20..fe2787e3d 100644
--- a/src/gui/CloneDialog.h
+++ b/src/gui/CloneDialog.h
@@ -32,7 +32,7 @@ class CloneDialog : public QDialog
 
 public:
     explicit CloneDialog(DatabaseWidget* parent = nullptr, Database* db = nullptr, Entry* entry = nullptr);
-    ~CloneDialog();
+    ~CloneDialog() override;
 
 private:
     QScopedPointer<Ui::CloneDialog> m_ui;
diff --git a/src/gui/DatabaseOpenWidget.h b/src/gui/DatabaseOpenWidget.h
index 8a26b3045..673032ba3 100644
--- a/src/gui/DatabaseOpenWidget.h
+++ b/src/gui/DatabaseOpenWidget.h
@@ -39,7 +39,7 @@ class DatabaseOpenWidget : public DialogyWidget
 
 public:
     explicit DatabaseOpenWidget(QWidget* parent = nullptr);
-    ~DatabaseOpenWidget();
+    ~DatabaseOpenWidget() override;
     void load(const QString& filename);
     QString filename();
     void clearForms();
diff --git a/src/gui/EditWidget.h b/src/gui/EditWidget.h
index c4997abae..b70dfc0f1 100644
--- a/src/gui/EditWidget.h
+++ b/src/gui/EditWidget.h
@@ -39,7 +39,7 @@ class EditWidget : public DialogyWidget
 
 public:
     explicit EditWidget(QWidget* parent = nullptr);
-    ~EditWidget();
+    ~EditWidget() override;
 
     void addPage(const QString& labelText, const QIcon& icon, QWidget* widget);
     bool hasPage(QWidget* widget);
diff --git a/src/gui/EditWidgetIcons.h b/src/gui/EditWidgetIcons.h
index 15e927d6c..3b40fae41 100644
--- a/src/gui/EditWidgetIcons.h
+++ b/src/gui/EditWidgetIcons.h
@@ -62,7 +62,7 @@ class EditWidgetIcons : public QWidget
 
 public:
     explicit EditWidgetIcons(QWidget* parent = nullptr);
-    ~EditWidgetIcons();
+    ~EditWidgetIcons() override;
 
     IconStruct state();
     void reset();
diff --git a/src/gui/EditWidgetProperties.h b/src/gui/EditWidgetProperties.h
index 30a983e98..679a14501 100644
--- a/src/gui/EditWidgetProperties.h
+++ b/src/gui/EditWidgetProperties.h
@@ -38,7 +38,7 @@ class EditWidgetProperties : public QWidget
 
 public:
     explicit EditWidgetProperties(QWidget* parent = nullptr);
-    ~EditWidgetProperties();
+    ~EditWidgetProperties() override;
 
     void setFields(const TimeInfo& timeInfo, const QUuid& uuid);
     void setCustomData(CustomData* customData);
diff --git a/src/gui/KMessageWidget.h b/src/gui/KMessageWidget.h
index d47e78f9c..7d6fb854f 100644
--- a/src/gui/KMessageWidget.h
+++ b/src/gui/KMessageWidget.h
@@ -130,8 +130,8 @@ public:
     /**
      * Destructor.
      */
-    ~KMessageWidget();
-    
+    ~KMessageWidget() override;
+
     /**
      * Get the text of this message widget.
      * @see setText()
diff --git a/src/gui/MainWindow.h b/src/gui/MainWindow.h
index 2fdc43ed1..e6a3ba0ac 100644
--- a/src/gui/MainWindow.h
+++ b/src/gui/MainWindow.h
@@ -48,7 +48,7 @@ class MainWindow : public QMainWindow
 
 public:
     MainWindow();
-    ~MainWindow();
+    ~MainWindow() override;
 
     QList<DatabaseWidget*> getOpenDatabases();
     void restoreConfigState();
diff --git a/src/gui/PasswordGeneratorWidget.h b/src/gui/PasswordGeneratorWidget.h
index 80b3f26de..a42c44d3a 100644
--- a/src/gui/PasswordGeneratorWidget.h
+++ b/src/gui/PasswordGeneratorWidget.h
@@ -45,7 +45,7 @@ public:
     };
 
     explicit PasswordGeneratorWidget(QWidget* parent = nullptr);
-    ~PasswordGeneratorWidget();
+    ~PasswordGeneratorWidget() override;
 
     void loadSettings();
     void saveSettings();
@@ -86,7 +86,7 @@ private:
     bool m_passwordGenerated = false;
     int m_firstCustomWordlistIndex;
 
-    void closeEvent(QCloseEvent* event);
+    void closeEvent(QCloseEvent* event) override;
     PasswordGenerator::CharClasses charClasses();
     PasswordGenerator::GeneratorFlags generatorFlags();
 
diff --git a/src/gui/TotpExportSettingsDialog.h b/src/gui/TotpExportSettingsDialog.h
index ed58dd073..03bd98aad 100644
--- a/src/gui/TotpExportSettingsDialog.h
+++ b/src/gui/TotpExportSettingsDialog.h
@@ -32,7 +32,7 @@ class TotpExportSettingsDialog : public QDialog
 
 public:
     explicit TotpExportSettingsDialog(DatabaseWidget* parent = nullptr, Entry* entry = nullptr);
-    ~TotpExportSettingsDialog();
+    ~TotpExportSettingsDialog() override;
 
 private slots:
     void copyToClipboard();
diff --git a/src/gui/WelcomeWidget.h b/src/gui/WelcomeWidget.h
index 15f93466c..675882340 100644
--- a/src/gui/WelcomeWidget.h
+++ b/src/gui/WelcomeWidget.h
@@ -32,7 +32,7 @@ class WelcomeWidget : public QWidget
 
 public:
     explicit WelcomeWidget(QWidget* parent = nullptr);
-    ~WelcomeWidget();
+    ~WelcomeWidget() override;
     void refreshLastDatabases();
 
 signals:
diff --git a/src/gui/csvImport/CsvImportWidget.h b/src/gui/csvImport/CsvImportWidget.h
index 1711e32a6..2f09c7b13 100644
--- a/src/gui/csvImport/CsvImportWidget.h
+++ b/src/gui/csvImport/CsvImportWidget.h
@@ -37,7 +37,7 @@ class CsvImportWidget : public QWidget
 
 public:
     explicit CsvImportWidget(QWidget* parent = nullptr);
-    ~CsvImportWidget();
+    ~CsvImportWidget() override;
     void load(const QString& filename, Database* const db);
 
 signals:
diff --git a/src/gui/csvImport/CsvParserModel.h b/src/gui/csvImport/CsvParserModel.h
index 5e979421c..aec430958 100644
--- a/src/gui/csvImport/CsvParserModel.h
+++ b/src/gui/csvImport/CsvParserModel.h
@@ -30,7 +30,7 @@ class CsvParserModel : public QAbstractTableModel, public CsvParser
 
 public:
     explicit CsvParserModel(QObject* parent = nullptr);
-    ~CsvParserModel();
+    ~CsvParserModel() override;
     void setFilename(const QString& filename);
     QString getFileInfo();
     bool parse();
diff --git a/src/gui/entry/EntryAttachmentsWidget.h b/src/gui/entry/EntryAttachmentsWidget.h
index 9d64ed31b..0f104a82a 100644
--- a/src/gui/entry/EntryAttachmentsWidget.h
+++ b/src/gui/entry/EntryAttachmentsWidget.h
@@ -37,7 +37,7 @@ class EntryAttachmentsWidget : public QWidget
     Q_PROPERTY(bool isButtonsVisible READ isButtonsVisible WRITE setButtonsVisible NOTIFY buttonsVisibleChanged)
 public:
     explicit EntryAttachmentsWidget(QWidget* parent = nullptr);
-    ~EntryAttachmentsWidget();
+    ~EntryAttachmentsWidget() override;
 
     const EntryAttachments* attachments() const;
     bool isReadOnly() const;
diff --git a/src/gui/group/EditGroupWidget.h b/src/gui/group/EditGroupWidget.h
index e61e38c54..412269c85 100644
--- a/src/gui/group/EditGroupWidget.h
+++ b/src/gui/group/EditGroupWidget.h
@@ -55,7 +55,7 @@ class EditGroupWidget : public EditWidget
 
 public:
     explicit EditGroupWidget(QWidget* parent = nullptr);
-    ~EditGroupWidget();
+    ~EditGroupWidget() override;
 
     void loadGroup(Group* group, bool create, const QSharedPointer<Database>& database);
     void clear();
diff --git a/src/gui/osutils/OSUtilsBase.h b/src/gui/osutils/OSUtilsBase.h
index 080a53413..5b827b83b 100644
--- a/src/gui/osutils/OSUtilsBase.h
+++ b/src/gui/osutils/OSUtilsBase.h
@@ -82,7 +82,7 @@ signals:
 
 protected:
     explicit OSUtilsBase(QObject* parent = nullptr);
-    virtual ~OSUtilsBase();
+    ~OSUtilsBase() override;
 };
 
 #endif // KEEPASSXC_OSUTILSBASE_H
diff --git a/src/gui/osutils/ScreenLockListener.h b/src/gui/osutils/ScreenLockListener.h
index 107d342a6..f8a3ceeec 100644
--- a/src/gui/osutils/ScreenLockListener.h
+++ b/src/gui/osutils/ScreenLockListener.h
@@ -27,7 +27,7 @@ class ScreenLockListener : public QObject
 
 public:
     ScreenLockListener(QWidget* parent = nullptr);
-    ~ScreenLockListener();
+    ~ScreenLockListener() override;
 
 signals:
     void screenLocked();
diff --git a/src/gui/reports/ReportsWidgetHibp.h b/src/gui/reports/ReportsWidgetHibp.h
index 2955358ad..5410417b2 100644
--- a/src/gui/reports/ReportsWidgetHibp.h
+++ b/src/gui/reports/ReportsWidgetHibp.h
@@ -43,7 +43,7 @@ class ReportsWidgetHibp : public QWidget
     Q_OBJECT
 public:
     explicit ReportsWidgetHibp(QWidget* parent = nullptr);
-    ~ReportsWidgetHibp();
+    ~ReportsWidgetHibp() override;
 
     void loadSettings(QSharedPointer<Database> db);
     void saveSettings();
diff --git a/src/gui/reports/ReportsWidgetStatistics.h b/src/gui/reports/ReportsWidgetStatistics.h
index cc11a75f5..02931891c 100644
--- a/src/gui/reports/ReportsWidgetStatistics.h
+++ b/src/gui/reports/ReportsWidgetStatistics.h
@@ -34,7 +34,7 @@ class ReportsWidgetStatistics : public QWidget
     Q_OBJECT
 public:
     explicit ReportsWidgetStatistics(QWidget* parent = nullptr);
-    ~ReportsWidgetStatistics();
+    ~ReportsWidgetStatistics() override;
 
     void loadSettings(QSharedPointer<Database> db);
     void saveSettings();
diff --git a/src/gui/widgets/ElidedLabel.h b/src/gui/widgets/ElidedLabel.h
index 5dd14891d..1f90d056e 100644
--- a/src/gui/widgets/ElidedLabel.h
+++ b/src/gui/widgets/ElidedLabel.h
@@ -51,7 +51,7 @@ private slots:
     void updateElidedText();
 
 private:
-    void resizeEvent(QResizeEvent* event);
+    void resizeEvent(QResizeEvent* event) override;
 
     Qt::TextElideMode m_elideMode;
     QString m_rawText;
diff --git a/src/streams/HashedBlockStream.h b/src/streams/HashedBlockStream.h
index e107c2cce..dc1c16a1a 100644
--- a/src/streams/HashedBlockStream.h
+++ b/src/streams/HashedBlockStream.h
@@ -29,7 +29,7 @@ class HashedBlockStream : public LayeredStream
 public:
     explicit HashedBlockStream(QIODevice* baseDevice);
     HashedBlockStream(QIODevice* baseDevice, qint32 blockSize);
-    ~HashedBlockStream();
+    ~HashedBlockStream() override;
 
     bool reset() override;
     void close() override;
diff --git a/src/streams/HmacBlockStream.h b/src/streams/HmacBlockStream.h
index 18f5e5301..691aa1e16 100644
--- a/src/streams/HmacBlockStream.h
+++ b/src/streams/HmacBlockStream.h
@@ -29,7 +29,7 @@ class HmacBlockStream : public LayeredStream
 public:
     explicit HmacBlockStream(QIODevice* baseDevice, QByteArray key);
     HmacBlockStream(QIODevice* baseDevice, QByteArray key, qint32 blockSize);
-    ~HmacBlockStream();
+    ~HmacBlockStream() override;
 
     bool reset() override;
     void close() override;
diff --git a/src/streams/LayeredStream.h b/src/streams/LayeredStream.h
index 0e1156d70..643ddfb45 100644
--- a/src/streams/LayeredStream.h
+++ b/src/streams/LayeredStream.h
@@ -26,7 +26,7 @@ class LayeredStream : public QIODevice
 
 public:
     explicit LayeredStream(QIODevice* baseDevice);
-    virtual ~LayeredStream();
+    ~LayeredStream() override;
 
     bool isSequential() const override;
     bool open(QIODevice::OpenMode mode) override;
diff --git a/src/streams/SymmetricCipherStream.h b/src/streams/SymmetricCipherStream.h
index 3f11dc8bd..10c6e4774 100644
--- a/src/streams/SymmetricCipherStream.h
+++ b/src/streams/SymmetricCipherStream.h
@@ -30,7 +30,7 @@ class SymmetricCipherStream : public LayeredStream
 
 public:
     SymmetricCipherStream(QIODevice* baseDevice);
-    ~SymmetricCipherStream();
+    ~SymmetricCipherStream() override;
     bool
     init(SymmetricCipher::Mode mode, SymmetricCipher::Direction direction, const QByteArray& key, const QByteArray& iv);
     bool open(QIODevice::OpenMode mode) override;
diff --git a/src/streams/qtiocompressor.h b/src/streams/qtiocompressor.h
index cebd98293..458b2991d 100644
--- a/src/streams/qtiocompressor.h
+++ b/src/streams/qtiocompressor.h
@@ -56,18 +56,20 @@ Q_OBJECT
 public:
 enum StreamFormat { ZlibFormat, GzipFormat, RawZipFormat };
     QtIOCompressor(QIODevice *device, int compressionLevel = 6, int bufferSize = 65500);
-    ~QtIOCompressor();
+    ~QtIOCompressor() override;
     void setStreamFormat(StreamFormat format);
     StreamFormat streamFormat() const;
     static bool isGzipSupported();
-    bool isSequential() const;
-    bool open(OpenMode mode);
-    void close();
+    bool isSequential() const override;
+    bool open(OpenMode mode) override;
+    void close() override;
     void flush();
-    qint64 bytesAvailable() const;
+    qint64 bytesAvailable() const override;
+
 protected:
-    qint64 readData(char * data, qint64 maxSize);
-    qint64 writeData(const char * data, qint64 maxSize);
+    qint64 readData(char* data, qint64 maxSize) override;
+    qint64 writeData(const char* data, qint64 maxSize) override;
+
 private:
     static bool checkGzipSupport(const char * const versionString);
     QtIOCompressorPrivate *d_ptr;