Modernize codebase using clang-tidy

Using the following checks:
 * modernize-use-nullptr
 * modernize-use-override
 * modernize-use-using
 * modernize-use-bool-literals

41 files changed, 212 insertions, 212 deletions

diff --git a/src/base/QXmppArchiveIq.h b/src/base/QXmppArchiveIq.h
index 1f82174a..a631e096 100644
--- a/src/base/QXmppArchiveIq.h
+++ b/src/base/QXmppArchiveIq.h
@@ -111,8 +111,8 @@ public:
     static bool isArchiveChatIq(const QDomElement &element);
 
 protected:
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -153,8 +153,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -186,8 +186,8 @@ public:
     static bool isArchiveRemoveIq(const QDomElement &element);
 
 protected:
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -218,8 +218,8 @@ public:
     static bool isArchiveRetrieveIq(const QDomElement &element);
 
 protected:
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -239,8 +239,8 @@ public:
     static bool isArchivePrefIq(const QDomElement &element);
 
 protected:
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 };
 
diff --git a/src/base/QXmppBindIq.h b/src/base/QXmppBindIq.h
index c1434d54..fec856c9 100644
--- a/src/base/QXmppBindIq.h
+++ b/src/base/QXmppBindIq.h
@@ -48,8 +48,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppByteStreamIq.h b/src/base/QXmppByteStreamIq.h
index 67a25fea..c94f1d9b 100644
--- a/src/base/QXmppByteStreamIq.h
+++ b/src/base/QXmppByteStreamIq.h
@@ -78,8 +78,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppCodec_p.h b/src/base/QXmppCodec_p.h
index 8ee51f4f..d7f80d7e 100644
--- a/src/base/QXmppCodec_p.h
+++ b/src/base/QXmppCodec_p.h
@@ -60,8 +60,8 @@ class QXmppG711aCodec : public QXmppCodec
 public:
     QXmppG711aCodec(int clockrate);
 
-    qint64 encode(QDataStream &input, QDataStream &output);
-    qint64 decode(QDataStream &input, QDataStream &output);
+    qint64 encode(QDataStream &input, QDataStream &output) override;
+    qint64 decode(QDataStream &input, QDataStream &output) override;
 
 private:
     int m_frequency;
@@ -76,8 +76,8 @@ class QXmppG711uCodec : public QXmppCodec
 public:
     QXmppG711uCodec(int clockrate);
 
-    qint64 encode(QDataStream &input, QDataStream &output);
-    qint64 decode(QDataStream &input, QDataStream &output);
+    qint64 encode(QDataStream &input, QDataStream &output) override;
+    qint64 decode(QDataStream &input, QDataStream &output) override;
 
 private:
     int m_frequency;
diff --git a/src/base/QXmppDataForm.cpp b/src/base/QXmppDataForm.cpp
index b500785c..0e909259 100644
--- a/src/base/QXmppDataForm.cpp
+++ b/src/base/QXmppDataForm.cpp
@@ -46,7 +46,7 @@ static field_type field_types[] = {
     {QXmppDataForm::Field::TextMultiField, "text-multi"},
     {QXmppDataForm::Field::TextPrivateField, "text-private"},
     {QXmppDataForm::Field::TextSingleField, "text-single"},
-    {static_cast<QXmppDataForm::Field::Type>(-1), NULL},
+    {static_cast<QXmppDataForm::Field::Type>(-1), nullptr},
 };
 
 class QXmppDataFormMediaPrivate : public QSharedData
diff --git a/src/base/QXmppDiscoveryIq.h b/src/base/QXmppDiscoveryIq.h
index 8de64dc7..edc2669d 100644
--- a/src/base/QXmppDiscoveryIq.h
+++ b/src/base/QXmppDiscoveryIq.h
@@ -99,8 +99,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppElement.cpp b/src/base/QXmppElement.cpp
index cd977817..7d0e33fa 100644
--- a/src/base/QXmppElement.cpp
+++ b/src/base/QXmppElement.cpp
@@ -46,12 +46,12 @@ public:
 };
 
 QXmppElementPrivate::QXmppElementPrivate()
-    : counter(1), parent(NULL)
+    : counter(1), parent(nullptr)
 {
 }
 
 QXmppElementPrivate::QXmppElementPrivate(const QDomElement &element)
-    : counter(1), parent(NULL)
+    : counter(1), parent(nullptr)
 {
     if (element.isNull())
         return;
@@ -207,7 +207,7 @@ void QXmppElement::removeChild(const QXmppElement &child)
 
     d->children.removeAll(child.d);
     child.d->counter.deref();
-    child.d->parent = NULL;
+    child.d->parent = nullptr;
 }
 
 QString QXmppElement::tagName() const
diff --git a/src/base/QXmppElement.h b/src/base/QXmppElement.h
index e7cc5596..a3647d0d 100644
--- a/src/base/QXmppElement.h
+++ b/src/base/QXmppElement.h
@@ -34,7 +34,7 @@ class QDomElement;
 class QXmppElement;
 class QXmppElementPrivate;
 
-typedef QList<QXmppElement> QXmppElementList;
+using QXmppElementList = QList<QXmppElement>;
 class QXMPP_EXPORT QXmppElement
 {
 public:
diff --git a/src/base/QXmppEntityTimeIq.h b/src/base/QXmppEntityTimeIq.h
index a5b7e2d5..1379ebce 100644
--- a/src/base/QXmppEntityTimeIq.h
+++ b/src/base/QXmppEntityTimeIq.h
@@ -44,8 +44,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppHttpUploadIq.h b/src/base/QXmppHttpUploadIq.h
index 47cd7595..63c2da23 100644
--- a/src/base/QXmppHttpUploadIq.h
+++ b/src/base/QXmppHttpUploadIq.h
@@ -42,7 +42,7 @@ class QXMPP_EXPORT QXmppHttpUploadRequestIq : public QXmppIq
 {
 public:
     QXmppHttpUploadRequestIq();
-    ~QXmppHttpUploadRequestIq();
+    ~QXmppHttpUploadRequestIq() override;
 
     QString fileName() const;
     void setFileName(const QString &filename);
@@ -57,8 +57,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -74,7 +74,7 @@ class QXMPP_EXPORT QXmppHttpUploadSlotIq : public QXmppIq
 {
 public:
     QXmppHttpUploadSlotIq();
-    ~QXmppHttpUploadSlotIq();
+    ~QXmppHttpUploadSlotIq() override;
 
     QUrl putUrl() const;
     void setPutUrl(const QUrl &putUrl);
@@ -89,8 +89,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppIbbIq.h b/src/base/QXmppIbbIq.h
index 732936c7..92828095 100644
--- a/src/base/QXmppIbbIq.h
+++ b/src/base/QXmppIbbIq.h
@@ -42,8 +42,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -63,8 +63,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -89,8 +89,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppIq.h b/src/base/QXmppIq.h
index c147bb78..e7451e7c 100644
--- a/src/base/QXmppIq.h
+++ b/src/base/QXmppIq.h
@@ -53,18 +53,18 @@ public:
 
     QXmppIq(QXmppIq::Type type = QXmppIq::Get);
     QXmppIq(const QXmppIq &other);
-    ~QXmppIq();
+    ~QXmppIq() override;
 
     QXmppIq& operator=(const QXmppIq &other);
 
     QXmppIq::Type type() const;
     void setType(QXmppIq::Type);
 
-    bool isXmppStanza() const;
+    bool isXmppStanza() const override;
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
 
 protected:
     virtual void parseElementFromChild(const QDomElement &element);
diff --git a/src/base/QXmppJingleIq.h b/src/base/QXmppJingleIq.h
index ea5d84ef..75a37e04 100644
--- a/src/base/QXmppJingleIq.h
+++ b/src/base/QXmppJingleIq.h
@@ -138,7 +138,7 @@ public:
     void parse(const QDomElement &element);
     void toXml(QXmlStreamWriter *writer) const;
 
-    static QXmppJingleCandidate::Type typeFromString(const QString &typeStr, bool *ok = 0);
+    static QXmppJingleCandidate::Type typeFromString(const QString &typeStr, bool *ok = nullptr);
     static QString typeToString(QXmppJingleCandidate::Type type);
     /// \endcond
 
@@ -289,7 +289,7 @@ public:
 
     QXmppJingleIq();
     QXmppJingleIq(const QXmppJingleIq &other);
-    ~QXmppJingleIq();
+    ~QXmppJingleIq() override;
 
     QXmppJingleIq& operator=(const QXmppJingleIq &other);
 
@@ -322,8 +322,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppLogger.cpp b/src/base/QXmppLogger.cpp
index 4b602b38..f429b969 100644
--- a/src/base/QXmppLogger.cpp
+++ b/src/base/QXmppLogger.cpp
@@ -32,7 +32,7 @@
 
 #include "QXmppLogger.h"
 
-QXmppLogger* QXmppLogger::m_logger = 0;
+QXmppLogger* QXmppLogger::m_logger = nullptr;
 
 static const char *typeName(QXmppLogger::MessageType type)
 {
@@ -116,7 +116,7 @@ public:
 
 QXmppLoggerPrivate::QXmppLoggerPrivate()
     : loggingType(QXmppLogger::NoLogging)
-    , logFile(0)
+    , logFile(nullptr)
     , logFilePath("QXmppClientLog.log")
     , messageTypes(QXmppLogger::AnyMessage)
 {
@@ -268,7 +268,7 @@ void QXmppLogger::reopen()
 {
     if (d->logFile) {
         delete d->logFile;
-        d->logFile = 0;
+        d->logFile = nullptr;
     }
 }
 
diff --git a/src/base/QXmppLogger.h b/src/base/QXmppLogger.h
index a75623b1..912dbd4c 100644
--- a/src/base/QXmppLogger.h
+++ b/src/base/QXmppLogger.h
@@ -74,8 +74,8 @@ public:
     };
     Q_DECLARE_FLAGS(MessageTypes, MessageType)
 
-    QXmppLogger(QObject *parent = 0);
-    ~QXmppLogger();
+    QXmppLogger(QObject *parent = nullptr);
+    ~QXmppLogger() override;
 
     static QXmppLogger* getLogger();
 
@@ -113,11 +113,11 @@ class QXMPP_EXPORT QXmppLoggable : public QObject
     Q_OBJECT
 
 public:
-    QXmppLoggable(QObject *parent = 0);
+    QXmppLoggable(QObject *parent = nullptr);
 
 protected:
     /// \cond
-    virtual void childEvent(QChildEvent *event);
+    void childEvent(QChildEvent *event) override;
     /// \endcond
 
     /// Logs a debugging message.
diff --git a/src/base/QXmppMamIq.h b/src/base/QXmppMamIq.h
index 78a6f943..65f0b3f5 100644
--- a/src/base/QXmppMamIq.h
+++ b/src/base/QXmppMamIq.h
@@ -47,8 +47,8 @@ public:
     static bool isMamQueryIq(const QDomElement &element);
 
 protected:
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
 
 private:
     QXmppDataForm m_form;
@@ -72,8 +72,8 @@ public:
     static bool isMamResultIq(const QDomElement &element);
 
 protected:
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
 
 private:
     QXmppResultSetReply m_resultSetReply;
diff --git a/src/base/QXmppMessage.h b/src/base/QXmppMessage.h
index 9021f0cb..2743ca13 100644
--- a/src/base/QXmppMessage.h
+++ b/src/base/QXmppMessage.h
@@ -90,7 +90,7 @@ public:
                  const QString& body = QString(), const QString& thread = QString());
 
     QXmppMessage(const QXmppMessage &other);
-    ~QXmppMessage();
+    ~QXmppMessage() override;
 
     QXmppMessage& operator=(const QXmppMessage &other);
 
@@ -150,7 +150,7 @@ public:
     bool isPrivate() const;
     void setPrivate(const bool);
 
-    bool isXmppStanza() const;
+    bool isXmppStanza() const override;
 
     // XEP-0066: Out of Band Data
     QString outOfBandUrl() const;
@@ -194,8 +194,8 @@ public:
     void setSpoilerHint(const QString&);
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppMixIq.h b/src/base/QXmppMixIq.h
index bc399706..4e3b71f8 100644
--- a/src/base/QXmppMixIq.h
+++ b/src/base/QXmppMixIq.h
@@ -51,7 +51,7 @@ public:
     };
 
     QXmppMixIq();
-    ~QXmppMixIq();
+    ~QXmppMixIq() override;
 
     QXmppMixIq::Type actionType() const;
     void setActionType(QXmppMixIq::Type);
@@ -74,8 +74,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement&);
-    void toXmlElementFromChild(QXmlStreamWriter*) const;
+    void parseElementFromChild(const QDomElement&) override;
+    void toXmlElementFromChild(QXmlStreamWriter*) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppMucIq.h b/src/base/QXmppMucIq.h
index 7a87eddc..b9b715f8 100644
--- a/src/base/QXmppMucIq.h
+++ b/src/base/QXmppMucIq.h
@@ -113,8 +113,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -141,8 +141,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppNonSASLAuth.h b/src/base/QXmppNonSASLAuth.h
index e888d4c2..4a457fe6 100644
--- a/src/base/QXmppNonSASLAuth.h
+++ b/src/base/QXmppNonSASLAuth.h
@@ -47,8 +47,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppPingIq.h b/src/base/QXmppPingIq.h
index c23381c5..3139dc13 100644
--- a/src/base/QXmppPingIq.h
+++ b/src/base/QXmppPingIq.h
@@ -30,7 +30,7 @@ class QXMPP_EXPORT QXmppPingIq : public QXmppIq
 {
 public:
     QXmppPingIq();
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     static bool isPingIq(const QDomElement &element);
 };
 
diff --git a/src/base/QXmppPresence.h b/src/base/QXmppPresence.h
index 25b6ea7f..d6ab980d 100644
--- a/src/base/QXmppPresence.h
+++ b/src/base/QXmppPresence.h
@@ -75,7 +75,7 @@ public:
 
     QXmppPresence(QXmppPresence::Type type = QXmppPresence::Available);
     QXmppPresence(const QXmppPresence &other);
-    ~QXmppPresence();
+    ~QXmppPresence() override;
 
     QXmppPresence& operator=(const QXmppPresence &other);
 
@@ -92,8 +92,8 @@ public:
     void setStatusText(const QString& statusText);
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 
     // XEP-0045: Multi-User Chat
@@ -139,7 +139,7 @@ public:
     QString mixUserNick() const;
     void setMixUserNick(const QString&);
 
-    bool isXmppStanza() const;
+    bool isXmppStanza() const override;
 
 private:
     QSharedDataPointer<QXmppPresencePrivate> d;
diff --git a/src/base/QXmppPubSubIq.h b/src/base/QXmppPubSubIq.h
index 77cd234e..741b25da 100644
--- a/src/base/QXmppPubSubIq.h
+++ b/src/base/QXmppPubSubIq.h
@@ -92,8 +92,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement&);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement&) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppRegisterIq.h b/src/base/QXmppRegisterIq.h
index c51035da..47fe12cc 100644
--- a/src/base/QXmppRegisterIq.h
+++ b/src/base/QXmppRegisterIq.h
@@ -59,8 +59,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppRosterIq.h b/src/base/QXmppRosterIq.h
index 1b8b747a..4d0205d4 100644
--- a/src/base/QXmppRosterIq.h
+++ b/src/base/QXmppRosterIq.h
@@ -98,7 +98,7 @@ public:
     };
 
     QXmppRosterIq();
-    ~QXmppRosterIq();
+    ~QXmppRosterIq() override;
 
     QString version() const;
     void setVersion(const QString&);
@@ -116,8 +116,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppRpcIq.h b/src/base/QXmppRpcIq.h
index ce406d4f..1edd31aa 100644
--- a/src/base/QXmppRpcIq.h
+++ b/src/base/QXmppRpcIq.h
@@ -60,8 +60,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -92,8 +92,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -117,8 +117,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppRtpChannel.cpp b/src/base/QXmppRtpChannel.cpp
index 61bf10f7..f80c7c4d 100644
--- a/src/base/QXmppRtpChannel.cpp
+++ b/src/base/QXmppRtpChannel.cpp
@@ -213,12 +213,12 @@ QXmppRtpAudioChannelPrivate::QXmppRtpAudioChannelPrivate()
     , incomingMaximum(0)
     , incomingPos(0)
     , incomingSequence(0)
-    , outgoingCodec(0)
+    , outgoingCodec(nullptr)
     , outgoingMarker(true)
     , outgoingPayloadNumbered(false)
     , outgoingSequence(1)
     , outgoingStamp(0)
-    , outgoingTimer(0)
+    , outgoingTimer(nullptr)
 {
     qRegisterMetaType<QXmppRtpAudioChannel::Tone>("QXmppRtpAudioChannel::Tone");
 }
@@ -240,7 +240,7 @@ QXmppCodec *QXmppRtpAudioChannelPrivate::codecForPayloadType(const QXmppJinglePa
     else if (payloadType.name().toLower() == "opus")
         return new QXmppOpusCodec(payloadType.clockrate(), payloadType.channels());
 #endif
-    return 0;
+    return nullptr;
 }
 
 /// Constructs a new RTP audio channel with the given \a parent.
@@ -349,7 +349,7 @@ void QXmppRtpAudioChannel::datagramReceived(const QByteArray &ba)
     d->incomingSequence = packet.sequence();
 
     // get or create codec
-    QXmppCodec *codec = 0;
+    QXmppCodec *codec = nullptr;
     const quint8 packetType = packet.type();
     if (!d->incomingCodecs.contains(packetType)) {
         foreach (const QXmppJinglePayloadType &payload, m_incomingPayloadTypes) {
@@ -497,7 +497,7 @@ void QXmppRtpAudioChannel::payloadTypesChanged()
     // delete outgoing codec
     if (d->outgoingCodec) {
         delete d->outgoingCodec;
-        d->outgoingCodec = 0;
+        d->outgoingCodec = nullptr;
     }
 
     // create outgoing codec
@@ -797,7 +797,7 @@ public:
 };
 
 QXmppRtpVideoChannelPrivate::QXmppRtpVideoChannelPrivate()
-    : encoder(0),
+    : encoder(nullptr),
     outgoingId(0),
     outgoingSequence(1),
     outgoingStamp(0)
@@ -925,7 +925,7 @@ void QXmppRtpVideoChannel::payloadTypesChanged()
         delete decoder;
     d->decoders.clear();
     foreach (const QXmppJinglePayloadType &payload, m_incomingPayloadTypes) {
-        QXmppVideoDecoder *decoder = 0;
+        QXmppVideoDecoder *decoder = nullptr;
         if (false)
             {}
 #ifdef QXMPP_USE_THEORA
@@ -945,10 +945,10 @@ void QXmppRtpVideoChannel::payloadTypesChanged()
     // refresh encoder
     if (d->encoder) {
         delete d->encoder;
-        d->encoder = 0;
+        d->encoder = nullptr;
     }
     foreach (const QXmppJinglePayloadType &payload, m_outgoingPayloadTypes) {
-        QXmppVideoEncoder *encoder = 0;
+        QXmppVideoEncoder *encoder = nullptr;
         if (false)
             {}
 #ifdef QXMPP_USE_THEORA
diff --git a/src/base/QXmppRtpChannel.h b/src/base/QXmppRtpChannel.h
index 0e0789da..9b68c7bc 100644
--- a/src/base/QXmppRtpChannel.h
+++ b/src/base/QXmppRtpChannel.h
@@ -98,16 +98,16 @@ public:
         Tone_D      ///< Tone for the D key.
     };
 
-    QXmppRtpAudioChannel(QObject *parent = 0);
-    ~QXmppRtpAudioChannel();
+    QXmppRtpAudioChannel(QObject *parent = nullptr);
+    ~QXmppRtpAudioChannel() override;
 
-    qint64 bytesAvailable() const;
-    void close();
-    bool isSequential() const;
-    QIODevice::OpenMode openMode() const;
+    qint64 bytesAvailable() const override;
+    void close() override;
+    bool isSequential() const override;
+    QIODevice::OpenMode openMode() const override;
     QXmppJinglePayloadType payloadType() const;
-    qint64 pos() const;
-    bool seek(qint64 pos);
+    qint64 pos() const override;
+    bool seek(qint64 pos) override;
 
 signals:
     /// \brief This signal is emitted when a datagram needs to be sent.
@@ -143,9 +143,9 @@ protected:
         emit logMessage(QXmppLogger::SentMessage, qxmpp_loggable_trace(message));
     }
 
-    void payloadTypesChanged();
-    qint64 readData(char * data, qint64 maxSize);
-    qint64 writeData(const char * data, qint64 maxSize);
+    void payloadTypesChanged() override;
+    qint64 readData(char * data, qint64 maxSize) override;
+    qint64 writeData(const char * data, qint64 maxSize) override;
     /// \endcond
 
 private slots:
@@ -263,11 +263,11 @@ class QXMPP_EXPORT QXmppRtpVideoChannel : public QXmppLoggable, public QXmppRtpC
     Q_OBJECT
 
 public:
-    QXmppRtpVideoChannel(QObject *parent = 0);
-    ~QXmppRtpVideoChannel();
+    QXmppRtpVideoChannel(QObject *parent = nullptr);
+    ~QXmppRtpVideoChannel() override;
 
-    void close();
-    QIODevice::OpenMode openMode() const;
+    void close() override;
+    QIODevice::OpenMode openMode() const override;
 
     // incoming stream
     QXmppVideoFormat decoderFormat() const;
@@ -287,7 +287,7 @@ public slots:
 
 protected:
     /// \cond
-    void payloadTypesChanged();
+    void payloadTypesChanged() override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppSasl.cpp b/src/base/QXmppSasl.cpp
index 6d57ee09..497fadf5 100644
--- a/src/base/QXmppSasl.cpp
+++ b/src/base/QXmppSasl.cpp
@@ -298,7 +298,7 @@ QXmppSaslClient* QXmppSaslClient::create(const QString &mechanism, QObject *pare
     } else if (mechanism == "X-OAUTH2") {
         return new QXmppSaslClientGoogle(parent);
     } else {
-        return 0;
+        return nullptr;
     }
 }
 
@@ -491,7 +491,7 @@ bool QXmppSaslClientFacebook::respond(const QByteArray &challenge, QByteArray &r
         QUrlQuery responseUrl;
         responseUrl.addQueryItem("access_token", password());
         responseUrl.addQueryItem("api_key", username());
-        responseUrl.addQueryItem("call_id", 0);
+        responseUrl.addQueryItem("call_id", nullptr);
         responseUrl.addQueryItem("method", requestUrl.queryItemValue("method"));
         responseUrl.addQueryItem("nonce", requestUrl.queryItemValue("nonce"));
         responseUrl.addQueryItem("v", "1.0");
@@ -681,7 +681,7 @@ QXmppSaslServer* QXmppSaslServer::create(const QString &mechanism, QObject *pare
     } else if (mechanism == "ANONYMOUS") {
         return new QXmppSaslServerAnonymous(parent);
     } else {
-        return 0;
+        return nullptr;
     }
 }
 
diff --git a/src/base/QXmppSasl_p.h b/src/base/QXmppSasl_p.h
index 90c2638c..1d460f01 100644
--- a/src/base/QXmppSasl_p.h
+++ b/src/base/QXmppSasl_p.h
@@ -52,8 +52,8 @@ class QXmppSaslServerPrivate;
 class QXMPP_AUTOTEST_EXPORT QXmppSaslClient : public QXmppLoggable
 {
 public:
-    QXmppSaslClient(QObject *parent = 0);
-    virtual ~QXmppSaslClient();
+    QXmppSaslClient(QObject *parent = nullptr);
+    ~QXmppSaslClient() override;
 
     QString host() const;
     void setHost(const QString &host);
@@ -71,7 +71,7 @@ public:
     virtual bool respond(const QByteArray &challenge, QByteArray &response) = 0;
 
     static QStringList availableMechanisms();
-    static QXmppSaslClient* create(const QString &mechanism, QObject *parent = 0);
+    static QXmppSaslClient* create(const QString &mechanism, QObject *parent = nullptr);
 
 private:
     QXmppSaslClientPrivate *d;
@@ -87,8 +87,8 @@ public:
         InputNeeded = 3
     };
 
-    QXmppSaslServer(QObject *parent = 0);
-    virtual ~QXmppSaslServer();
+    QXmppSaslServer(QObject *parent = nullptr);
+    ~QXmppSaslServer() override;
 
     QString username() const;
     void setUsername(const QString &username);
@@ -105,7 +105,7 @@ public:
     virtual QString mechanism() const = 0;
     virtual Response respond(const QByteArray &challenge, QByteArray &response) = 0;
 
-    static QXmppSaslServer* create(const QString &mechanism, QObject *parent = 0);
+    static QXmppSaslServer* create(const QString &mechanism, QObject *parent = nullptr);
 
 private:
     QXmppSaslServerPrivate *d;
@@ -133,8 +133,8 @@ public:
     void setValue(const QByteArray &value);
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -151,8 +151,8 @@ public:
     void setValue(const QByteArray &value);
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -168,8 +168,8 @@ public:
     void setCondition(const QString &condition);
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -185,8 +185,8 @@ public:
     void setValue(const QByteArray &value);
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
@@ -199,17 +199,17 @@ public:
     QXmppSaslSuccess();
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 };
 
 class QXmppSaslClientAnonymous : public QXmppSaslClient
 {
 public:
-    QXmppSaslClientAnonymous(QObject *parent = 0);
-    QString mechanism() const;
-    bool respond(const QByteArray &challenge, QByteArray &response);
+    QXmppSaslClientAnonymous(QObject *parent = nullptr);
+    QString mechanism() const override;
+    bool respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
@@ -218,9 +218,9 @@ private:
 class QXmppSaslClientDigestMd5 : public QXmppSaslClient
 {
 public:
-    QXmppSaslClientDigestMd5(QObject *parent = 0);
-    QString mechanism() const;
-    bool respond(const QByteArray &challenge, QByteArray &response);
+    QXmppSaslClientDigestMd5(QObject *parent = nullptr);
+    QString mechanism() const override;
+    bool respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     QByteArray m_cnonce;
@@ -233,9 +233,9 @@ private:
 class QXmppSaslClientFacebook : public QXmppSaslClient
 {
 public:
-    QXmppSaslClientFacebook(QObject *parent = 0);
-    QString mechanism() const;
-    bool respond(const QByteArray &challenge, QByteArray &response);
+    QXmppSaslClientFacebook(QObject *parent = nullptr);
+    QString mechanism() const override;
+    bool respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
@@ -244,9 +244,9 @@ private:
 class QXmppSaslClientGoogle : public QXmppSaslClient
 {
 public:
-    QXmppSaslClientGoogle(QObject *parent = 0);
-    QString mechanism() const;
-    bool respond(const QByteArray &challenge, QByteArray &response);
+    QXmppSaslClientGoogle(QObject *parent = nullptr);
+    QString mechanism() const override;
+    bool respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
@@ -255,9 +255,9 @@ private:
 class QXmppSaslClientPlain : public QXmppSaslClient
 {
 public:
-    QXmppSaslClientPlain(QObject *parent = 0);
-    QString mechanism() const;
-    bool respond(const QByteArray &challenge, QByteArray &response);
+    QXmppSaslClientPlain(QObject *parent = nullptr);
+    QString mechanism() const override;
+    bool respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
@@ -266,9 +266,9 @@ private:
 class QXmppSaslClientScram : public QXmppSaslClient
 {
 public:
-    QXmppSaslClientScram(QCryptographicHash::Algorithm algorithm, QObject *parent = 0);
-    QString mechanism() const;
-    bool respond(const QByteArray &challenge, QByteArray &response);
+    QXmppSaslClientScram(QCryptographicHash::Algorithm algorithm, QObject *parent = nullptr);
+    QString mechanism() const override;
+    bool respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     QCryptographicHash::Algorithm m_algorithm;
@@ -284,9 +284,9 @@ private:
 class QXmppSaslClientWindowsLive : public QXmppSaslClient
 {
 public:
-    QXmppSaslClientWindowsLive(QObject *parent = 0);
-    QString mechanism() const;
-    bool respond(const QByteArray &challenge, QByteArray &response);
+    QXmppSaslClientWindowsLive(QObject *parent = nullptr);
+    QString mechanism() const override;
+    bool respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
@@ -295,10 +295,10 @@ private:
 class QXmppSaslServerAnonymous : public QXmppSaslServer
 {
 public:
-    QXmppSaslServerAnonymous(QObject *parent = 0);
-    QString mechanism() const;
+    QXmppSaslServerAnonymous(QObject *parent = nullptr);
+    QString mechanism() const override;
 
-    Response respond(const QByteArray &challenge, QByteArray &response);
+    Response respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
@@ -307,10 +307,10 @@ private:
 class QXmppSaslServerDigestMd5 : public QXmppSaslServer
 {
 public:
-    QXmppSaslServerDigestMd5(QObject *parent = 0);
-    QString mechanism() const;
+    QXmppSaslServerDigestMd5(QObject *parent = nullptr);
+    QString mechanism() const override;
 
-    Response respond(const QByteArray &challenge, QByteArray &response);
+    Response respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     QByteArray m_cnonce;
@@ -323,10 +323,10 @@ private:
 class QXmppSaslServerFacebook : public QXmppSaslServer
 {
 public:
-    QXmppSaslServerFacebook(QObject *parent = 0);
-    QString mechanism() const;
+    QXmppSaslServerFacebook(QObject *parent = nullptr);
+    QString mechanism() const override;
 
-    Response respond(const QByteArray &challenge, QByteArray &response);
+    Response respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
@@ -335,10 +335,10 @@ private:
 class QXmppSaslServerPlain : public QXmppSaslServer
 {
 public:
-    QXmppSaslServerPlain(QObject *parent = 0);
-    QString mechanism() const;
+    QXmppSaslServerPlain(QObject *parent = nullptr);
+    QString mechanism() const override;
 
-    Response respond(const QByteArray &challenge, QByteArray &response);
+    Response respond(const QByteArray &challenge, QByteArray &response) override;
 
 private:
     int m_step;
diff --git a/src/base/QXmppSessionIq.h b/src/base/QXmppSessionIq.h
index 7a1b444b..7cc375fb 100644
--- a/src/base/QXmppSessionIq.h
+++ b/src/base/QXmppSessionIq.h
@@ -42,7 +42,7 @@ public:
 
 private:
     /// \cond
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 };
 
diff --git a/src/base/QXmppSocks.h b/src/base/QXmppSocks.h
index 114c7ab9..31af8ca9 100644
--- a/src/base/QXmppSocks.h
+++ b/src/base/QXmppSocks.h
@@ -36,7 +36,7 @@ class QXMPP_EXPORT QXmppSocksClient : public QTcpSocket
     Q_OBJECT
 
 public:
-    QXmppSocksClient(const QString &proxyHost, quint16 proxyPort, QObject *parent=0);
+    QXmppSocksClient(const QString &proxyHost, quint16 proxyPort, QObject *parent=nullptr);
     void connectToHost(const QString &hostName, quint16 hostPort);
 
 signals:
@@ -59,7 +59,7 @@ class QXMPP_EXPORT QXmppSocksServer : public QObject
     Q_OBJECT
 
 public:
-    QXmppSocksServer(QObject *parent=0);
+    QXmppSocksServer(QObject *parent=nullptr);
     void close();
     bool listen(quint16 port = 0);
 
diff --git a/src/base/QXmppStream.cpp b/src/base/QXmppStream.cpp
index 000f3b75..e3fa5bfd 100644
--- a/src/base/QXmppStream.cpp
+++ b/src/base/QXmppStream.cpp
@@ -61,7 +61,7 @@ public:
 };
 
 QXmppStreamPrivate::QXmppStreamPrivate()
-    : socket(0), streamManagementEnabled(false), lastOutgoingSequenceNumber(0), lastIncomingSequenceNumber(0)
+    : socket(nullptr), streamManagementEnabled(false), lastOutgoingSequenceNumber(0), lastIncomingSequenceNumber(0)
 {
 }
 
diff --git a/src/base/QXmppStream.h b/src/base/QXmppStream.h
index d05b29fa..271b3400 100644
--- a/src/base/QXmppStream.h
+++ b/src/base/QXmppStream.h
@@ -44,7 +44,7 @@ class QXMPP_EXPORT QXmppStream : public QXmppLoggable
 
 public:
     QXmppStream(QObject *parent);
-    ~QXmppStream();
+    ~QXmppStream() override;
 
     virtual bool isConnected() const;
     bool sendPacket(const QXmppStanza&);
diff --git a/src/base/QXmppStreamFeatures.h b/src/base/QXmppStreamFeatures.h
index dfb20bb9..5a697b83 100644
--- a/src/base/QXmppStreamFeatures.h
+++ b/src/base/QXmppStreamFeatures.h
@@ -82,8 +82,8 @@ public:
     void setRegisterMode(const Mode &registerMode);
 
     /// \cond
-    void parse(const QDomElement &element);
-    void toXml(QXmlStreamWriter *writer) const;
+    void parse(const QDomElement &element) override;
+    void toXml(QXmlStreamWriter *writer) const override;
     /// \endcond
 
     static bool isStreamFeatures(const QDomElement &element);
diff --git a/src/base/QXmppStreamInitiationIq_p.h b/src/base/QXmppStreamInitiationIq_p.h
index efff0d29..8f227020 100644
--- a/src/base/QXmppStreamInitiationIq_p.h
+++ b/src/base/QXmppStreamInitiationIq_p.h
@@ -70,8 +70,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppStun.cpp b/src/base/QXmppStun.cpp
index 7b8a8ad3..36fc4d26 100644
--- a/src/base/QXmppStun.cpp
+++ b/src/base/QXmppStun.cpp
@@ -1683,8 +1683,8 @@ CandidatePair::CandidatePair(int component, bool controlling, QObject *parent)
     : QXmppLoggable(parent)
     , nominated(false)
     , nominating(false)
-    , transport(0)
-    , transaction(0)
+    , transport(nullptr)
+    , transaction(nullptr)
     , m_component(component)
     , m_controlling(controlling)
     , m_state(WaitingState)
@@ -1790,14 +1790,14 @@ private:
 };
 
 QXmppIceComponentPrivate::QXmppIceComponentPrivate(int component_, QXmppIcePrivate *config_, QXmppIceComponent *qq)
-    : activePair(0)
+    : activePair(nullptr)
     , component(component_)
     , config(config_)
-    , fallbackPair(0)
+    , fallbackPair(nullptr)
     , gatheringState(QXmppIceConnection::NewGatheringState)
     , peerReflexivePriority(0)
-    , timer(0)
-    , turnAllocation(0)
+    , timer(nullptr)
+    , turnAllocation(nullptr)
     , turnConfigured(false)
     , q(qq)
 {
@@ -1845,7 +1845,7 @@ CandidatePair* QXmppIceComponentPrivate::findPair(QXmppStunTransaction *transact
         if (pair->transaction == transaction)
             return pair;
     }
-    return 0;
+    return nullptr;
 }
 
 void QXmppIceComponentPrivate::performCheck(CandidatePair *pair, bool nominate)
@@ -2029,7 +2029,7 @@ void QXmppIceComponent::close()
         transport->disconnectFromHost();
     d->turnAllocation->disconnectFromHost();
     d->timer->stop();
-    d->activePair = 0;
+    d->activePair = nullptr;
 }
 
 /// Starts ICE connectivity checks.
@@ -2047,7 +2047,7 @@ void QXmppIceComponent::connectToHost()
 
 bool QXmppIceComponent::isConnected() const
 {
-    return d->activePair != 0;
+    return d->activePair != nullptr;
 }
 
 /// Returns the list of local candidates.
@@ -2082,7 +2082,7 @@ void QXmppIceComponent::handleDatagram(const QByteArray &buffer, const QHostAddr
     }
 
     // check if it's STUN
-    QXmppStunTransaction *stunTransaction = 0;
+    QXmppStunTransaction *stunTransaction = nullptr;
     foreach (QXmppStunTransaction *t, d->stunTransactions.keys()) {
         if (t->request().id() == messageId &&
             d->stunTransactions.value(t) == transport) {
@@ -2125,7 +2125,7 @@ void QXmppIceComponent::handleDatagram(const QByteArray &buffer, const QHostAddr
     }
 
     // process message from peer
-    CandidatePair *pair = 0;
+    CandidatePair *pair = nullptr;
     if (message.messageClass() == QXmppStunMessage::Request)
     {
         // check for role conflict
@@ -2238,7 +2238,7 @@ void QXmppIceComponent::handleDatagram(const QByteArray &buffer, const QHostAddr
         if (!d->activePair || pair->priority() > d->activePair->priority()) {
             info(QString("ICE pair selected %1 (priority: %2)").arg(
                 pair->toString(), QString::number(pair->priority())));
-            const bool wasConnected = (d->activePair != 0);
+            const bool wasConnected = (d->activePair != nullptr);
             d->activePair = pair;
             if (!wasConnected)
                 emit connected();
@@ -2273,7 +2273,7 @@ void QXmppIceComponent::transactionFinished()
                 transaction->response().errorPhrase));
             pair->setState(CandidatePair::FailedState);
         }
-        pair->transaction = 0;
+        pair->transaction = nullptr;
         return;
     }
 
@@ -2518,7 +2518,7 @@ public:
 };
 
 QXmppIceConnectionPrivate::QXmppIceConnectionPrivate()
-    : connectTimer(NULL)
+    : connectTimer(nullptr)
     , gatheringState(QXmppIceConnection::NewGatheringState)
     , turnPort(0)
 {
diff --git a/src/base/QXmppStun.h b/src/base/QXmppStun.h
index 973e1f90..4fa3e34b 100644
--- a/src/base/QXmppStun.h
+++ b/src/base/QXmppStun.h
@@ -113,7 +113,7 @@ public:
     void setUsername(const QString &username);
 
     QByteArray encode(const QByteArray &key = QByteArray(), bool addFingerprint = true) const;
-    bool decode(const QByteArray &buffer, const QByteArray &key = QByteArray(), QStringList *errors = 0);
+    bool decode(const QByteArray &buffer, const QByteArray &key = QByteArray(), QStringList *errors = nullptr);
     QString toString() const;
     static quint16 peekType(const QByteArray &buffer, quint32 &cookie, QByteArray &id);
 
@@ -167,14 +167,14 @@ class QXMPP_EXPORT QXmppIceComponent : public QXmppLoggable
     Q_OBJECT
 
 public:
-    ~QXmppIceComponent();
+    ~QXmppIceComponent() override;
 
     int component() const;
     bool isConnected() const;
     QList<QXmppJingleCandidate> localCandidates() const;
 
     static QList<QHostAddress> discoverAddresses();
-    static QList<QUdpSocket*> reservePorts(const QList<QHostAddress> &addresses, int count, QObject *parent = 0);
+    static QList<QUdpSocket*> reservePorts(const QList<QHostAddress> &addresses, int count, QObject *parent = nullptr);
 
 public slots:
     void close();
@@ -203,7 +203,7 @@ signals:
     void localCandidatesChanged();
 
 private:
-    QXmppIceComponent(int component, QXmppIcePrivate *config, QObject *parent=0);
+    QXmppIceComponent(int component, QXmppIcePrivate *config, QObject *parent=nullptr);
 
     QXmppIceComponentPrivate *d;
     friend class QXmppIceComponentPrivate;
@@ -252,8 +252,8 @@ public:
         CompleteGatheringState
     };
 
-    QXmppIceConnection(QObject *parent = 0);
-    ~QXmppIceConnection();
+    QXmppIceConnection(QObject *parent = nullptr);
+    ~QXmppIceConnection() override;
 
     QXmppIceComponent *component(int component);
     void addComponent(int component);
diff --git a/src/base/QXmppStun_p.h b/src/base/QXmppStun_p.h
index ea87234f..c3c8eb1d 100644
--- a/src/base/QXmppStun_p.h
+++ b/src/base/QXmppStun_p.h
@@ -77,8 +77,8 @@ class QXMPP_EXPORT QXmppIceTransport : public QXmppLoggable
     Q_OBJECT
 
 public:
-    QXmppIceTransport(QObject *parent = 0);
-    ~QXmppIceTransport();
+    QXmppIceTransport(QObject *parent = nullptr);
+    ~QXmppIceTransport() override;
 
     virtual QXmppJingleCandidate localCandidate(int component) const = 0;
     virtual qint64 writeDatagram(const QByteArray &data, const QHostAddress &host, quint16 port) = 0;
@@ -110,8 +110,8 @@ public:
         ClosingState
     };
 
-    QXmppTurnAllocation(QObject *parent = 0);
-    ~QXmppTurnAllocation();
+    QXmppTurnAllocation(QObject *parent = nullptr);
+    ~QXmppTurnAllocation() override;
 
     QHostAddress relayedHost() const;
     quint16 relayedPort() const;
@@ -121,8 +121,8 @@ public:
     void setUser(const QString &user);
     void setPassword(const QString &password);
 
-    QXmppJingleCandidate localCandidate(int component) const;
-    qint64 writeDatagram(const QByteArray &data, const QHostAddress &host, quint16 port);
+    QXmppJingleCandidate localCandidate(int component) const override;
+    qint64 writeDatagram(const QByteArray &data, const QHostAddress &host, quint16 port) override;
 
 signals:
     /// \brief This signal is emitted once TURN allocation succeeds.
@@ -133,7 +133,7 @@ signals:
 
 public slots:
     void connectToHost();
-    void disconnectFromHost();
+    void disconnectFromHost() override;
 
 private slots:
     void readyRead();
@@ -180,14 +180,14 @@ class QXMPP_EXPORT QXmppUdpTransport : public QXmppIceTransport
     Q_OBJECT
 
 public:
-    QXmppUdpTransport(QUdpSocket *socket, QObject *parent = 0);
-    ~QXmppUdpTransport();
+    QXmppUdpTransport(QUdpSocket *socket, QObject *parent = nullptr);
+    ~QXmppUdpTransport() override;
 
-    QXmppJingleCandidate localCandidate(int component) const;
-    qint64 writeDatagram(const QByteArray &data, const QHostAddress &host, quint16 port);
+    QXmppJingleCandidate localCandidate(int component) const override;
+    qint64 writeDatagram(const QByteArray &data, const QHostAddress &host, quint16 port) override;
 
 public slots:
-    void disconnectFromHost();
+    void disconnectFromHost() override;
 
 private slots:
     void readyRead();
diff --git a/src/base/QXmppVCardIq.h b/src/base/QXmppVCardIq.h
index 26456d00..e0b9ec87 100644
--- a/src/base/QXmppVCardIq.h
+++ b/src/base/QXmppVCardIq.h
@@ -228,7 +228,7 @@ class QXMPP_EXPORT QXmppVCardIq : public QXmppIq
 public:
     QXmppVCardIq(const QString& bareJid = QString());
     QXmppVCardIq(const QXmppVCardIq &other);
-    ~QXmppVCardIq();
+    ~QXmppVCardIq() override;
 
     QXmppVCardIq& operator=(const QXmppVCardIq &other);
 
@@ -283,8 +283,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement&);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement&) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private:
diff --git a/src/base/QXmppVersionIq.h b/src/base/QXmppVersionIq.h
index 2d953a99..3f558165 100644
--- a/src/base/QXmppVersionIq.h
+++ b/src/base/QXmppVersionIq.h
@@ -49,8 +49,8 @@ public:
 
 protected:
     /// \cond
-    void parseElementFromChild(const QDomElement &element);
-    void toXmlElementFromChild(QXmlStreamWriter *writer) const;
+    void parseElementFromChild(const QDomElement &element) override;
+    void toXmlElementFromChild(QXmlStreamWriter *writer) const override;
     /// \endcond
 
 private: