diff --git a/kdecoration/breezesettingsprovider.cpp b/kdecoration/breezesettingsprovider.cpp
--- a/kdecoration/breezesettingsprovider.cpp
+++ b/kdecoration/breezesettingsprovider.cpp
@@ -105,7 +105,7 @@
                     if( className.isEmpty() )
                     {
                         // retrieve class name
-                        KWindowInfo info( client->windowId(), 0, NET::WM2WindowClass );
+                        KWindowInfo info( client->windowId(), nullptr, NET::WM2WindowClass );
                         QString window_className( QString::fromUtf8(info.windowClassName()) );
                         QString window_class( QString::fromUtf8(info.windowClassClass()) );
                         className = window_className + QStringLiteral(" ") + window_class;
diff --git a/kdecoration/breezesizegrip.cpp b/kdecoration/breezesizegrip.cpp
--- a/kdecoration/breezesizegrip.cpp
+++ b/kdecoration/breezesizegrip.cpp
@@ -227,7 +227,7 @@
         */
         QPoint rootPosition( position );
         xcb_get_geometry_cookie_t cookie( xcb_get_geometry( connection, winId() ) );
-        ScopedPointer<xcb_get_geometry_reply_t> reply( xcb_get_geometry_reply( connection, cookie, 0x0 ) );
+        ScopedPointer<xcb_get_geometry_reply_t> reply( xcb_get_geometry_reply( connection, cookie, nullptr ) );
         if( reply )
         {
 
@@ -237,7 +237,7 @@
                 -reply.data()->border_width,
                 -reply.data()->border_width ) );
 
-            ScopedPointer< xcb_translate_coordinates_reply_t> coordReply( xcb_translate_coordinates_reply( connection, coordCookie, 0x0 ) );
+            ScopedPointer< xcb_translate_coordinates_reply_t> coordReply( xcb_translate_coordinates_reply( connection, coordCookie, nullptr ) );
 
             if( coordReply )
             {
@@ -254,7 +254,7 @@
             // create atom if not found
             const QString atomName( "_NET_WM_MOVERESIZE" );
             xcb_intern_atom_cookie_t cookie( xcb_intern_atom( connection, false, atomName.size(), qPrintable( atomName ) ) );
-            ScopedPointer<xcb_intern_atom_reply_t> reply( xcb_intern_atom_reply( connection, cookie, 0x0 ) );
+            ScopedPointer<xcb_intern_atom_reply_t> reply( xcb_intern_atom_reply( connection, cookie, nullptr ) );
             m_moveResizeAtom = reply ? reply->atom:0;
 
         }
diff --git a/kdecoration/config/breezedetectwidget.cpp b/kdecoration/config/breezedetectwidget.cpp
--- a/kdecoration/config/breezedetectwidget.cpp
+++ b/kdecoration/config/breezedetectwidget.cpp
@@ -110,7 +110,7 @@
         // use a dialog, so that all user input is blocked
         // use WX11BypassWM and moving away so that it's not actually visible
         // grab only mouse, so that keyboard can be used e.g. for switching windows
-        m_grabber = new QDialog( 0, Qt::X11BypassWindowManagerHint );
+        m_grabber = new QDialog( nullptr, Qt::X11BypassWindowManagerHint );
         m_grabber->move( -1000, -1000 );
         m_grabber->setModal( true );
         m_grabber->show();
@@ -134,7 +134,7 @@
 
         // delete old m_grabber
         delete m_grabber;
-        m_grabber = 0;
+        m_grabber = nullptr;
 
         // check button
         if( static_cast< QMouseEvent* >( e )->button() != Qt::LeftButton ) return true;
diff --git a/kdecoration/config/breezeexceptiondialog.cpp b/kdecoration/config/breezeexceptiondialog.cpp
--- a/kdecoration/config/breezeexceptiondialog.cpp
+++ b/kdecoration/config/breezeexceptiondialog.cpp
@@ -177,7 +177,7 @@
         }
 
         delete m_detectDialog;
-        m_detectDialog = 0;
+        m_detectDialog = nullptr;
 
     }
 
diff --git a/kdecoration/config/breezeexceptionlistwidget.h b/kdecoration/config/breezeexceptionlistwidget.h
--- a/kdecoration/config/breezeexceptionlistwidget.h
+++ b/kdecoration/config/breezeexceptionlistwidget.h
@@ -41,7 +41,7 @@
         public:
 
         //* constructor
-        explicit ExceptionListWidget( QWidget* = 0 );
+        explicit ExceptionListWidget( QWidget* = nullptr );
 
         //* set exceptions
         void setExceptions( const InternalSettingsList& );
diff --git a/kdecoration/config/breezeitemmodel.h b/kdecoration/config/breezeitemmodel.h
--- a/kdecoration/config/breezeitemmodel.h
+++ b/kdecoration/config/breezeitemmodel.h
@@ -38,7 +38,7 @@
         public:
 
         //* constructor
-        explicit ItemModel(QObject *parent = 0);
+        explicit ItemModel(QObject *parent = nullptr);
 
         //* destructor
         virtual ~ItemModel()
diff --git a/kdecoration/config/breezelistmodel.h b/kdecoration/config/breezelistmodel.h
--- a/kdecoration/config/breezelistmodel.h
+++ b/kdecoration/config/breezelistmodel.h
@@ -58,7 +58,7 @@
         // typedef QSet<ValueType> Set;
 
         //! constructor
-        ListModel(QObject *parent = 0):
+        ListModel(QObject *parent = nullptr):
             ItemModel( parent )
         {}
 
@@ -72,7 +72,7 @@
         //! flags
         Qt::ItemFlags flags(const QModelIndex &index) const override
         {
-            if (!index.isValid()) return 0;
+            if (!index.isValid()) return nullptr;
             return Qt::ItemIsEnabled | Qt::ItemIsSelectable;
         }
 
diff --git a/kstyle/animations/breezetransitionwidget.h b/kstyle/animations/breezetransitionwidget.h
--- a/kstyle/animations/breezetransitionwidget.h
+++ b/kstyle/animations/breezetransitionwidget.h
@@ -150,7 +150,7 @@
         //@}
 
         //* grap pixmap
-        QPixmap grab( QWidget* = 0, QRect = QRect() );
+        QPixmap grab( QWidget* = nullptr, QRect = QRect() );
 
         //* true if animated
         virtual bool isAnimated() const
diff --git a/kstyle/animations/breezetransitionwidget.cpp b/kstyle/animations/breezetransitionwidget.cpp
--- a/kstyle/animations/breezetransitionwidget.cpp
+++ b/kstyle/animations/breezetransitionwidget.cpp
@@ -212,7 +212,7 @@
         if( widget->autoFillBackground() )
         { widgets.append( widget ); }
 
-        QWidget *parent(0);
+        QWidget *parent(nullptr);
 
         // get highest level parent
         for( parent = widget->parentWidget(); parent; parent = parent->parentWidget() )
@@ -262,7 +262,7 @@
         for( int i = widgets.size() - 1; i>=0; i-- )
         {
             QWidget* w = widgets.at(i);
-            w->render( &p, -widget->mapTo( w, rect.topLeft() ), rect, 0 );
+            w->render( &p, -widget->mapTo( w, rect.topLeft() ), rect, nullptr );
         }
 
         // end
diff --git a/kstyle/breezeframeshadow.cpp b/kstyle/breezeframeshadow.cpp
--- a/kstyle/breezeframeshadow.cpp
+++ b/kstyle/breezeframeshadow.cpp
@@ -140,7 +140,7 @@
             if( FrameShadow* shadow = qobject_cast<FrameShadow*>(child) )
             {
                 shadow->hide();
-                shadow->setParent(0);
+                shadow->setParent(nullptr);
                 shadow->deleteLater();
             }
         }
@@ -202,7 +202,7 @@
     //____________________________________________________________________________________
     void FrameShadowFactory::installShadow( QWidget* widget, Helper& helper, Side area ) const
     {
-        FrameShadow *shadow(0);
+        FrameShadow *shadow(nullptr);
         shadow = new FrameShadow( area, helper );
         shadow->setParent(widget);
         shadow->hide();
diff --git a/kstyle/breezehelper.cpp b/kstyle/breezehelper.cpp
--- a/kstyle/breezehelper.cpp
+++ b/kstyle/breezehelper.cpp
@@ -48,7 +48,7 @@
     //____________________________________________________________________
     #if BREEZE_USE_KDE4
     Helper::Helper( const QByteArray& name ):
-        _componentData( name, 0, KComponentData::SkipMainComponentRegistration ),
+        _componentData( name, nullptr, KComponentData::SkipMainComponentRegistration ),
         _config( _componentData.config() )
     { init(); }
     #endif
diff --git a/kstyle/breezeshadowhelper.cpp b/kstyle/breezeshadowhelper.cpp
--- a/kstyle/breezeshadowhelper.cpp
+++ b/kstyle/breezeshadowhelper.cpp
@@ -409,7 +409,7 @@
         if( !_gc )
         {
             _gc = xcb_generate_id( Helper::connection() );
-            xcb_create_gc( Helper::connection(), _gc, pixmap, 0, 0x0 );
+            xcb_create_gc( Helper::connection(), _gc, pixmap, 0, nullptr );
         }
 
         // create image from QPixmap and assign to pixmap
diff --git a/kstyle/breezestyle.cpp b/kstyle/breezestyle.cpp
--- a/kstyle/breezestyle.cpp
+++ b/kstyle/breezestyle.cpp
@@ -1088,7 +1088,7 @@
                 QMouseEvent* mouseEvent( static_cast<QMouseEvent*>( event ) );
 
                 // get frame framewidth
-                const int frameWidth( pixelMetric( PM_DefaultFrameWidth, 0, widget ) );
+                const int frameWidth( pixelMetric( PM_DefaultFrameWidth, nullptr, widget ) );
 
                 // find list of scrollbars
                 QList<QScrollBar*> scrollBars;
@@ -3609,7 +3609,7 @@
         {
 
             // need to adjust clipRect in order not to render outside of frame
-            const int frameWidth( pixelMetric( PM_DefaultFrameWidth, 0, scrollArea ) );
+            const int frameWidth( pixelMetric( PM_DefaultFrameWidth, nullptr, scrollArea ) );
             painter->setClipRect( insideMargin( scrollArea->rect(), frameWidth ) );
             painter->setBrush( scrollArea->viewport()->palette().color( scrollArea->viewport()->backgroundRole() ) );
             painter->setPen( Qt::NoPen );
@@ -4701,7 +4701,7 @@
             const auto color = _helper->focusColor( palette );
             const auto outlineColor = _helper->focusOutlineColor( palette );
 
-            Sides sides = 0;
+            Sides sides = nullptr;
             if( !menuItemOption->menuRect.isNull() )
             {
                 if( rect.top() <= menuItemOption->menuRect.top() ) sides |= SideTop;
diff --git a/kstyle/breezestyleplugin.h b/kstyle/breezestyleplugin.h
--- a/kstyle/breezestyleplugin.h
+++ b/kstyle/breezestyleplugin.h
@@ -37,7 +37,7 @@
         public:
 
         //* constructor
-        explicit StylePlugin(QObject *parent = 0):
+        explicit StylePlugin(QObject *parent = nullptr):
             QStylePlugin(parent)
         {}
 
diff --git a/kstyle/config/breezestyleconfig.cpp b/kstyle/config/breezestyleconfig.cpp
--- a/kstyle/config/breezestyleconfig.cpp
+++ b/kstyle/config/breezestyleconfig.cpp
@@ -97,7 +97,7 @@
         Kdelibs4Migration migration;
         const QString kde4ConfigDirPath = migration.saveLocation("config");
 
-        QScopedPointer<KConfig> kde4Config(StyleConfigData::self()->config()->copyTo(kde4ConfigDirPath+"/breezerc", 0));
+        QScopedPointer<KConfig> kde4Config(StyleConfigData::self()->config()->copyTo(kde4ConfigDirPath+"/breezerc", nullptr));
         kde4Config->sync();
         #endif