diff --git a/src/core/composer/qgscomposerlegend.cpp b/src/core/composer/qgscomposerlegend.cpp
index 182703d5f77..737fb6da994 100644
--- a/src/core/composer/qgscomposerlegend.cpp
+++ b/src/core/composer/qgscomposerlegend.cpp
@@ -624,20 +624,20 @@ void QgsComposerLegend::setComposerMap( const QgsComposerMap *map )
 {
   if ( mComposerMap )
   {
-    disconnect( mComposerMap, SIGNAL( destroyed( QObject * ) ), this, SLOT( invalidateCurrentMap() ) );
-    disconnect( mComposerMap, SIGNAL( itemChanged() ), this, SLOT( updateFilterByMap() ) );
-    disconnect( mComposerMap, SIGNAL( extentChanged() ), this, SLOT( updateFilterByMap() ) );
-    disconnect( mComposerMap, SIGNAL( layerStyleOverridesChanged() ), this, SLOT( mapLayerStyleOverridesChanged() ) );
+    disconnect( mComposerMap, &QObject::destroyed, this, &QgsComposerLegend::invalidateCurrentMap );
+    disconnect( mComposerMap, &QgsComposerObject::itemChanged, this, &QgsComposerLegend::updateFilterByMapAndRedraw );
+    disconnect( mComposerMap, &QgsComposerMap::extentChanged, this, &QgsComposerLegend::updateFilterByMapAndRedraw );
+    disconnect( mComposerMap, &QgsComposerMap::layerStyleOverridesChanged, this, &QgsComposerLegend::mapLayerStyleOverridesChanged );
   }
 
   mComposerMap = map;
 
   if ( map )
   {
-    QObject::connect( map, SIGNAL( destroyed( QObject * ) ), this, SLOT( invalidateCurrentMap() ) );
-    QObject::connect( map, SIGNAL( itemChanged() ), this, SLOT( updateFilterByMap() ) );
-    QObject::connect( map, SIGNAL( extentChanged() ), this, SLOT( updateFilterByMap() ) );
-    QObject::connect( map, SIGNAL( layerStyleOverridesChanged() ), this, SLOT( mapLayerStyleOverridesChanged() ) );
+    connect( map, &QObject::destroyed, this, &QgsComposerLegend::invalidateCurrentMap );
+    connect( map, &QgsComposerObject::itemChanged, this, &QgsComposerLegend::updateFilterByMapAndRedraw );
+    connect( map, &QgsComposerMap::extentChanged, this, &QgsComposerLegend::updateFilterByMapAndRedraw );
+    connect( map, &QgsComposerMap::layerStyleOverridesChanged, this, &QgsComposerLegend::mapLayerStyleOverridesChanged );
   }
 
   updateItem();
@@ -684,6 +684,11 @@ void QgsComposerLegend::refreshDataDefinedProperty( const QgsComposerObject::Dat
   QgsComposerObject::refreshDataDefinedProperty( property, context );
 }
 
+void QgsComposerLegend::updateFilterByMapAndRedraw()
+{
+  updateFilterByMap( true );
+}
+
 void QgsComposerLegend::mapLayerStyleOverridesChanged()
 {
   if ( !mComposerMap )
diff --git a/src/core/composer/qgscomposerlegend.h b/src/core/composer/qgscomposerlegend.h
index 23711e7eea3..d04758b352f 100644
--- a/src/core/composer/qgscomposerlegend.h
+++ b/src/core/composer/qgscomposerlegend.h
@@ -288,6 +288,9 @@ class CORE_EXPORT QgsComposerLegend : public QgsComposerItem
 
 
   private slots:
+
+    void updateFilterByMapAndRedraw();
+
     void updateFilterByMap( bool redraw = true );
 
     //! update legend in case style of associated map has changed
diff --git a/src/core/gps/qextserialport/posix_qextserialport.cpp b/src/core/gps/qextserialport/posix_qextserialport.cpp
index ef59cb3d1e5..72637f4ae91 100644
--- a/src/core/gps/qextserialport/posix_qextserialport.cpp
+++ b/src/core/gps/qextserialport/posix_qextserialport.cpp
@@ -721,7 +721,7 @@ bool QextSerialPort::open(OpenMode mode)
 
             if (queryMode() == QextSerialPort::EventDriven) {
                 readNotifier = new QSocketNotifier(fd, QSocketNotifier::Read, this);
-                connect(readNotifier, SIGNAL(activated(int)), this, SIGNAL(readyRead()));
+                connect(readNotifier, &QSocketNotifier::activated, this, [=] { emit readyRead(); } );
             }
         } else {
             qDebug() << "could not open file:" << strerror(errno);
diff --git a/src/core/gps/qextserialport/qextserialenumerator.h b/src/core/gps/qextserialport/qextserialenumerator.h
index a4af415e5db..fcdeb652cd3 100644
--- a/src/core/gps/qextserialport/qextserialenumerator.h
+++ b/src/core/gps/qextserialport/qextserialenumerator.h
@@ -88,10 +88,10 @@ class QextSerialRegistrationWidget : public QWidget
   \b Example
   \code
   QextSerialEnumerator* enumerator = new QextSerialEnumerator();
-  connect(enumerator, SIGNAL(deviceDiscovered(const QextPortInfo &)),
-             myClass, SLOT(onDeviceDiscovered(const QextPortInfo &)));
-  connect(enumerator, SIGNAL(deviceRemoved(const QextPortInfo &)),
-             myClass, SLOT(onDeviceRemoved(const QextPortInfo &)));
+  connect(enumerator, &QextSerialEnumerator::deviceDiscovered,
+             myClass, &MyObject::onDeviceDiscovered);
+  connect(enumerator, &QextSerialEnumerator::deviceRemoved,
+             myClass, &MyObject::onDeviceRemoved);
   \endcode
 
   \section Credits
diff --git a/src/core/gps/qextserialport/qextserialport.h b/src/core/gps/qextserialport/qextserialport.h
index 76d6e95c98f..dee04bf8bf3 100644
--- a/src/core/gps/qextserialport/qextserialport.h
+++ b/src/core/gps/qextserialport/qextserialport.h
@@ -150,7 +150,7 @@ to use, since you never have to worry about checking for new data.
 \b Example
 \code
 QextSerialPort* port = new QextSerialPort("COM1", QextSerialPort::EventDriven);
-connect(port, SIGNAL(readyRead()), myClass, SLOT(onDataAvailable()));
+connect(port, &QextSerialPort::readyRead, myClass, &MyObject::onDataAvailable);
 port->open();
 
 void MyClass::onDataAvailable() {
diff --git a/src/core/gps/qgsgpsconnection.cpp b/src/core/gps/qgsgpsconnection.cpp
index 3c59edd2def..18e63cbb5a3 100644
--- a/src/core/gps/qgsgpsconnection.cpp
+++ b/src/core/gps/qgsgpsconnection.cpp
@@ -32,7 +32,7 @@
 QgsGPSConnection::QgsGPSConnection( QIODevice *dev ): QObject( nullptr ), mSource( dev ), mStatus( NotConnected )
 {
   clearLastGPSInformation();
-  QObject::connect( dev, SIGNAL( readyRead() ), this, SLOT( parseData() ) );
+  QObject::connect( dev, &QIODevice::readyRead, this, &QgsGPSConnection::parseData );
 }
 
 QgsGPSConnection::~QgsGPSConnection()
diff --git a/src/core/gps/qgsgpsdetector.cpp b/src/core/gps/qgsgpsdetector.cpp
index ad28ff5e007..1e1e9e77d72 100644
--- a/src/core/gps/qgsgpsdetector.cpp
+++ b/src/core/gps/qgsgpsdetector.cpp
@@ -183,8 +183,8 @@ void QgsGPSDetector::advance()
     }
   }
 
-  connect( mConn, SIGNAL( stateChanged( const QgsGPSInformation & ) ), this, SLOT( detected( const QgsGPSInformation & ) ) );
-  connect( mConn, SIGNAL( destroyed( QObject * ) ), this, SLOT( connDestroyed( QObject * ) ) );
+  connect( mConn, &QgsGPSConnection::stateChanged, this, static_cast < void ( QgsGPSDetector::* )( const QgsGPSInformation & ) >( &QgsGPSDetector::detected ) );
+  connect( mConn, &QObject::destroyed, this, &QgsGPSDetector::connDestroyed );
 
   // leave 2s to pickup a valid string
   QTimer::singleShot( 2000, this, SLOT( advance() ) );
diff --git a/src/core/gps/qgsqtlocationconnection.cpp b/src/core/gps/qgsqtlocationconnection.cpp
index 8c52b8a3e24..c93c943e2aa 100644
--- a/src/core/gps/qgsqtlocationconnection.cpp
+++ b/src/core/gps/qgsqtlocationconnection.cpp
@@ -171,10 +171,10 @@ void QgsQtLocationConnection::startGPS()
       locationDataSource->setUpdateInterval( 1000 );
       // Whenever the location data source signals that the current
       // position is updated, the positionUpdated function is called.
-      QObject::connect( locationDataSource,
-                        SIGNAL( positionUpdated( QGeoPositionInfo ) ),
+      QObject::connect( locationDataSource.data(),
+                        &QGeoPositionInfoSource::positionUpdated,
                         this,
-                        SLOT( positionUpdated( QGeoPositionInfo ) ) );
+                        &QgsQtLocationConnection::positionUpdated );
       // Start listening for position updates
       locationDataSource->startUpdates();
     }
@@ -204,22 +204,18 @@ void QgsQtLocationConnection::startSatelliteMonitor()
       // Whenever the satellite info source signals that the number of
       // satellites in use is updated, the satellitesInUseUpdated function
       // is called
-      QObject::connect( satelliteInfoSource,
-                        SIGNAL( satellitesInUseUpdated(
-                                  const QList<QGeoSatelliteInfo> & ) ),
+      QObject::connect( satelliteInfoSource.data(),
+                        &QGeoSatelliteInfoSource::satellitesInUseUpdated,
                         this,
-                        SLOT( satellitesInUseUpdated(
-                                const QList<QGeoSatelliteInfo> & ) ) );
+                        &QgsQtLocationConnection::satellitesInUseUpdated );
 
       // Whenever the satellite info source signals that the number of
       // satellites in view is updated, the satellitesInViewUpdated function
       // is called
-      QObject::connect( satelliteInfoSource,
-                        SIGNAL( satellitesInViewUpdated(
-                                  const QList<QGeoSatelliteInfo> & ) ),
+      QObject::connect( satelliteInfoSource.data(),
+                        &QGeoSatelliteInfoSource::satellitesInViewUpdated,
                         this,
-                        SLOT( satellitesInViewUpdated(
-                                const QList<QGeoSatelliteInfo> & ) ) );
+                        &QgsQtLocationConnection::satellitesInViewUpdated );
 
       // Start listening for satellite updates
       satelliteInfoSource->startUpdates();
diff --git a/src/core/layertree/qgslayertreemodel.cpp b/src/core/layertree/qgslayertreemodel.cpp
index 1c4777fb401..6896a9fdee3 100644
--- a/src/core/layertree/qgslayertreemodel.cpp
+++ b/src/core/layertree/qgslayertreemodel.cpp
@@ -866,9 +866,10 @@ void QgsLayerTreeModel::connectToLayer( QgsLayerTreeLayer *nodeLayer )
     // using unique connection because there may be temporarily more nodes for a layer than just one
     // which would create multiple connections, however disconnect() would disconnect all multiple connections
     // even if we wanted to disconnect just one connection in each call.
-    connect( layer, SIGNAL( editingStarted() ), this, SLOT( layerNeedsUpdate() ), Qt::UniqueConnection );
-    connect( layer, SIGNAL( editingStopped() ), this, SLOT( layerNeedsUpdate() ), Qt::UniqueConnection );
-    connect( layer, SIGNAL( layerModified() ), this, SLOT( layerNeedsUpdate() ), Qt::UniqueConnection );
+    QgsVectorLayer *vl = qobject_cast< QgsVectorLayer * >( layer );
+    connect( vl, &QgsVectorLayer::editingStarted, this, &QgsLayerTreeModel::layerNeedsUpdate, Qt::UniqueConnection );
+    connect( vl, &QgsVectorLayer::editingStopped, this, &QgsLayerTreeModel::layerNeedsUpdate, Qt::UniqueConnection );
+    connect( vl, &QgsVectorLayer::layerModified, this, &QgsLayerTreeModel::layerNeedsUpdate, Qt::UniqueConnection );
   }
 }
 
diff --git a/src/core/layertree/qgslayertreemodellegendnode.cpp b/src/core/layertree/qgslayertreemodellegendnode.cpp
index 350a69b7966..8dd19497a63 100644
--- a/src/core/layertree/qgslayertreemodellegendnode.cpp
+++ b/src/core/layertree/qgslayertreemodellegendnode.cpp
@@ -603,9 +603,9 @@ QImage QgsWmsLegendNode::getLegendGraphic() const
     mFetcher.reset( prov->getLegendGraphicFetcher( ms ) );
     if ( mFetcher )
     {
-      connect( mFetcher.get(), SIGNAL( finish( const QImage & ) ), this, SLOT( getLegendGraphicFinished( const QImage & ) ) );
-      connect( mFetcher.get(), SIGNAL( error( const QString & ) ), this, SLOT( getLegendGraphicErrored( const QString & ) ) );
-      connect( mFetcher.get(), SIGNAL( progress( qint64, qint64 ) ), this, SLOT( getLegendGraphicProgress( qint64, qint64 ) ) );
+      connect( mFetcher.get(), &QgsImageFetcher::finish, this, &QgsWmsLegendNode::getLegendGraphicFinished );
+      connect( mFetcher.get(), &QgsImageFetcher::error, this, &QgsWmsLegendNode::getLegendGraphicErrored );
+      connect( mFetcher.get(), &QgsImageFetcher::progress, this, &QgsWmsLegendNode::getLegendGraphicProgress );
       mFetcher->start();
     } // else QgsDebugMsg("XXX No legend supported?");
 
diff --git a/src/core/layertree/qgslayertreenode.cpp b/src/core/layertree/qgslayertreenode.cpp
index d462f2e1b6b..51e2f02296c 100644
--- a/src/core/layertree/qgslayertreenode.cpp
+++ b/src/core/layertree/qgslayertreenode.cpp
@@ -207,17 +207,18 @@ void QgsLayerTreeNode::insertChildrenPrivate( int index, QList<QgsLayerTreeNode
   emit willAddChildren( this, index, indexTo );
   for ( int i = 0; i < nodes.count(); ++i )
   {
-    mChildren.insert( index + i, nodes[i] );
+    QgsLayerTreeNode *node = nodes.at( i );
+    mChildren.insert( index + i, node );
 
     // forward the signal towards the root
-    connect( nodes[i], SIGNAL( willAddChildren( QgsLayerTreeNode *, int, int ) ), this, SIGNAL( willAddChildren( QgsLayerTreeNode *, int, int ) ) );
-    connect( nodes[i], SIGNAL( addedChildren( QgsLayerTreeNode *, int, int ) ), this, SIGNAL( addedChildren( QgsLayerTreeNode *, int, int ) ) );
-    connect( nodes[i], SIGNAL( willRemoveChildren( QgsLayerTreeNode *, int, int ) ), this, SIGNAL( willRemoveChildren( QgsLayerTreeNode *, int, int ) ) );
-    connect( nodes[i], SIGNAL( removedChildren( QgsLayerTreeNode *, int, int ) ), this, SIGNAL( removedChildren( QgsLayerTreeNode *, int, int ) ) );
-    connect( nodes[i], SIGNAL( customPropertyChanged( QgsLayerTreeNode *, QString ) ), this, SIGNAL( customPropertyChanged( QgsLayerTreeNode *, QString ) ) );
-    connect( nodes[i], &QgsLayerTreeNode::visibilityChanged, this, &QgsLayerTreeNode::visibilityChanged );
-    connect( nodes[i], SIGNAL( expandedChanged( QgsLayerTreeNode *, bool ) ), this, SIGNAL( expandedChanged( QgsLayerTreeNode *, bool ) ) );
-    connect( nodes[i], SIGNAL( nameChanged( QgsLayerTreeNode *, QString ) ), this, SIGNAL( nameChanged( QgsLayerTreeNode *, QString ) ) );
+    connect( node, &QgsLayerTreeNode::willAddChildren, this, &QgsLayerTreeNode::willAddChildren );
+    connect( node, &QgsLayerTreeNode::addedChildren, this, &QgsLayerTreeNode::addedChildren );
+    connect( node, &QgsLayerTreeNode::willRemoveChildren, this, &QgsLayerTreeNode::willRemoveChildren );
+    connect( node, &QgsLayerTreeNode::removedChildren, this, &QgsLayerTreeNode::removedChildren );
+    connect( node, &QgsLayerTreeNode::customPropertyChanged, this, &QgsLayerTreeNode::customPropertyChanged );
+    connect( node, &QgsLayerTreeNode::visibilityChanged, this, &QgsLayerTreeNode::visibilityChanged );
+    connect( node, &QgsLayerTreeNode::expandedChanged, this, &QgsLayerTreeNode::expandedChanged );
+    connect( node, &QgsLayerTreeNode::nameChanged, this, &QgsLayerTreeNode::nameChanged );
   }
   emit addedChildren( this, index, indexTo );
 }
diff --git a/src/core/qgsbrowsermodel.cpp b/src/core/qgsbrowsermodel.cpp
index e7df5fb336d..faa4625925e 100644
--- a/src/core/qgsbrowsermodel.cpp
+++ b/src/core/qgsbrowsermodel.cpp
@@ -46,8 +46,8 @@ QgsBrowserModel::QgsBrowserModel( QObject *parent )
   , mFavorites( nullptr )
   , mProjectHome( nullptr )
 {
-  connect( QgsProject::instance(), SIGNAL( readProject( const QDomDocument & ) ), this, SLOT( updateProjectHome() ) );
-  connect( QgsProject::instance(), SIGNAL( writeProject( QDomDocument & ) ), this, SLOT( updateProjectHome() ) );
+  connect( QgsProject::instance(), &QgsProject::readProject, this, &QgsBrowserModel::updateProjectHome );
+  connect( QgsProject::instance(), &QgsProject::writeProject, this, &QgsBrowserModel::updateProjectHome );
   addRootItems();
 }
 
@@ -413,18 +413,18 @@ void QgsBrowserModel::itemStateChanged( QgsDataItem *item, QgsDataItem::State ol
 }
 void QgsBrowserModel::connectItem( QgsDataItem *item )
 {
-  connect( item, SIGNAL( beginInsertItems( QgsDataItem *, int, int ) ),
-           this, SLOT( beginInsertItems( QgsDataItem *, int, int ) ) );
-  connect( item, SIGNAL( endInsertItems() ),
-           this, SLOT( endInsertItems() ) );
-  connect( item, SIGNAL( beginRemoveItems( QgsDataItem *, int, int ) ),
-           this, SLOT( beginRemoveItems( QgsDataItem *, int, int ) ) );
-  connect( item, SIGNAL( endRemoveItems() ),
-           this, SLOT( endRemoveItems() ) );
-  connect( item, SIGNAL( dataChanged( QgsDataItem * ) ),
-           this, SLOT( itemDataChanged( QgsDataItem * ) ) );
-  connect( item, SIGNAL( stateChanged( QgsDataItem *, QgsDataItem::State ) ),
-           this, SLOT( itemStateChanged( QgsDataItem *, QgsDataItem::State ) ) );
+  connect( item, &QgsDataItem::beginInsertItems,
+           this, &QgsBrowserModel::beginInsertItems );
+  connect( item, &QgsDataItem::endInsertItems,
+           this, &QgsBrowserModel::endInsertItems );
+  connect( item, &QgsDataItem::beginRemoveItems,
+           this, &QgsBrowserModel::beginRemoveItems );
+  connect( item, &QgsDataItem::endRemoveItems,
+           this, &QgsBrowserModel::endRemoveItems );
+  connect( item, &QgsDataItem::dataChanged,
+           this, &QgsBrowserModel::itemDataChanged );
+  connect( item, &QgsDataItem::stateChanged,
+           this, &QgsBrowserModel::itemStateChanged );
 }
 
 QStringList QgsBrowserModel::mimeTypes() const
diff --git a/src/core/qgscontexthelp.cpp b/src/core/qgscontexthelp.cpp
index 1e7d720dd36..805d375daac 100644
--- a/src/core/qgscontexthelp.cpp
+++ b/src/core/qgscontexthelp.cpp
@@ -58,9 +58,9 @@ QProcess *QgsContextHelp::start()
   QProcess *process = new QProcess;
 
   // Delete this object if the process terminates
-  connect( process, SIGNAL( finished( int, QProcess::ExitStatus ) ), SLOT( processExited() ) );
+  connect( process, static_cast < void ( QProcess::* )( int ) >( &QProcess::finished ), this, [ = ] { processExited(); } );
 
-  connect( process, SIGNAL( error( QProcess::ProcessError ) ), this, SLOT( error( QProcess::ProcessError ) ) );
+  connect( process, static_cast < void ( QProcess::* )( QProcess::ProcessError ) >( &QProcess::error ), this, &QgsContextHelp::error );
 
 #ifdef Q_OS_WIN
   if ( QgsApplication::isRunningFromBuildDir() )
diff --git a/src/core/qgsdataitem.cpp b/src/core/qgsdataitem.cpp
index ba927b4b506..ac92f4ffc2c 100644
--- a/src/core/qgsdataitem.cpp
+++ b/src/core/qgsdataitem.cpp
@@ -406,7 +406,7 @@ void QgsDataItem::setParent( QgsDataItem *parent )
     connect( this, &QgsDataItem::beginInsertItems, parent, &QgsDataItem::beginInsertItems );
     connect( this, &QgsDataItem::endInsertItems, parent, &QgsDataItem::endInsertItems );
     connect( this, &QgsDataItem::beginRemoveItems, parent, &QgsDataItem::beginRemoveItems );
-    connect( this, SIGNAL( endRemoveItems() ), parent, SIGNAL( endRemoveItems() ) );
+    connect( this, &QgsDataItem::endRemoveItems, parent, &QgsDataItem::endRemoveItems );
     connect( this, &QgsDataItem::dataChanged, parent, &QgsDataItem::dataChanged );
     connect( this, &QgsDataItem::stateChanged, parent, &QgsDataItem::stateChanged );
   }
diff --git a/src/core/qgsgeometryvalidator.cpp b/src/core/qgsgeometryvalidator.cpp
index b9e76c6a315..ffe079228e6 100644
--- a/src/core/qgsgeometryvalidator.cpp
+++ b/src/core/qgsgeometryvalidator.cpp
@@ -354,7 +354,7 @@ void QgsGeometryValidator::addError( const QgsGeometry::Error &e )
 void QgsGeometryValidator::validateGeometry( const QgsGeometry *g, QList<QgsGeometry::Error> &errors )
 {
   QgsGeometryValidator *gv = new QgsGeometryValidator( g, &errors );
-  connect( gv, SIGNAL( errorFound( QgsGeometry::Error ) ), gv, SLOT( addError( QgsGeometry::Error ) ) );
+  connect( gv, &QgsGeometryValidator::errorFound, gv, &QgsGeometryValidator::addError );
   gv->run();
   gv->wait();
 }
diff --git a/src/core/qgsgml.cpp b/src/core/qgsgml.cpp
index de560fae6da..778fa74139a 100644
--- a/src/core/qgsgml.cpp
+++ b/src/core/qgsgml.cpp
@@ -93,8 +93,8 @@ int QgsGml::getFeatures( const QString &uri, QgsWkbTypes::Type *wkbType, QgsRect
     }
   }
 
-  connect( reply, SIGNAL( finished() ), this, SLOT( setFinished() ) );
-  connect( reply, SIGNAL( downloadProgress( qint64, qint64 ) ), this, SLOT( handleProgressEvent( qint64, qint64 ) ) );
+  connect( reply, &QNetworkReply::finished, this, &QgsGml::setFinished );
+  connect( reply, &QNetworkReply::downloadProgress, this, &QgsGml::handleProgressEvent );
 
   //find out if there is a QGIS main window. If yes, display a progress dialog
   QProgressDialog *progressDialog = nullptr;
@@ -112,9 +112,9 @@ int QgsGml::getFeatures( const QString &uri, QgsWkbTypes::Type *wkbType, QgsRect
   {
     progressDialog = new QProgressDialog( tr( "Loading GML data\n%1" ).arg( mTypeName ), tr( "Abort" ), 0, 0, mainWindow );
     progressDialog->setWindowModality( Qt::ApplicationModal );
-    connect( this, SIGNAL( dataReadProgress( int ) ), progressDialog, SLOT( setValue( int ) ) );
-    connect( this, SIGNAL( totalStepsUpdate( int ) ), progressDialog, SLOT( setMaximum( int ) ) );
-    connect( progressDialog, SIGNAL( canceled() ), this, SLOT( setFinished() ) );
+    connect( this, &QgsGml::dataReadProgress, progressDialog, &QProgressDialog::setValue );
+    connect( this, &QgsGml::totalStepsUpdate, progressDialog, &QProgressDialog::setMaximum );
+    connect( progressDialog, &QProgressDialog::canceled, this, &QgsGml::setFinished );
     progressDialog->show();
   }
 
diff --git a/src/core/qgsmaplayerlegend.cpp b/src/core/qgsmaplayerlegend.cpp
index d4b21286313..3761ae3ac03 100644
--- a/src/core/qgsmaplayerlegend.cpp
+++ b/src/core/qgsmaplayerlegend.cpp
@@ -179,7 +179,7 @@ void QgsMapLayerLegendUtils::applyLayerNodeProperties( QgsLayerTreeLayer *nodeLa
 QgsDefaultVectorLayerLegend::QgsDefaultVectorLayerLegend( QgsVectorLayer *vl )
   : mLayer( vl )
 {
-  connect( mLayer, SIGNAL( rendererChanged() ), this, SIGNAL( itemsChanged() ) );
+  connect( mLayer, &QgsMapLayer::rendererChanged, this, &QgsMapLayerLegend::itemsChanged );
 }
 
 QList<QgsLayerTreeModelLegendNode *> QgsDefaultVectorLayerLegend::createLayerTreeModelLegendNodes( QgsLayerTreeLayer *nodeLayer )
@@ -229,7 +229,7 @@ QList<QgsLayerTreeModelLegendNode *> QgsDefaultVectorLayerLegend::createLayerTre
 QgsDefaultRasterLayerLegend::QgsDefaultRasterLayerLegend( QgsRasterLayer *rl )
   : mLayer( rl )
 {
-  connect( mLayer, SIGNAL( rendererChanged() ), this, SIGNAL( itemsChanged() ) );
+  connect( mLayer, &QgsMapLayer::rendererChanged, this, &QgsMapLayerLegend::itemsChanged );
 }
 
 QList<QgsLayerTreeModelLegendNode *> QgsDefaultRasterLayerLegend::createLayerTreeModelLegendNodes( QgsLayerTreeLayer *nodeLayer )
diff --git a/src/core/qgsmaplayermodel.cpp b/src/core/qgsmaplayermodel.cpp
index fbc8271e08e..282ae2012f5 100644
--- a/src/core/qgsmaplayermodel.cpp
+++ b/src/core/qgsmaplayermodel.cpp
@@ -29,7 +29,7 @@ QgsMapLayerModel::QgsMapLayerModel( const QList<QgsMapLayer *> &layers, QObject
   , mAllowEmpty( false )
   , mShowCrs( false )
 {
-  connect( QgsProject::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( removeLayers( QStringList ) ) );
+  connect( QgsProject::instance(), static_cast < void ( QgsProject::* )( const QStringList & ) >( &QgsProject::layersWillBeRemoved ), this, &QgsMapLayerModel::removeLayers );
   addLayers( layers );
 }
 
@@ -40,8 +40,8 @@ QgsMapLayerModel::QgsMapLayerModel( QObject *parent )
   , mAllowEmpty( false )
   , mShowCrs( false )
 {
-  connect( QgsProject::instance(), SIGNAL( layersAdded( QList<QgsMapLayer *> ) ), this, SLOT( addLayers( QList<QgsMapLayer *> ) ) );
-  connect( QgsProject::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( removeLayers( QStringList ) ) );
+  connect( QgsProject::instance(), &QgsProject::layersAdded, this, &QgsMapLayerModel::addLayers );
+  connect( QgsProject::instance(), static_cast < void ( QgsProject::* )( const QStringList & ) >( &QgsProject::layersWillBeRemoved ), this, &QgsMapLayerModel::removeLayers );
   addLayers( QgsProject::instance()->mapLayers().values() );
 }
 
diff --git a/src/core/qgsmaprenderersequentialjob.cpp b/src/core/qgsmaprenderersequentialjob.cpp
index 2020105573e..95494f91e87 100644
--- a/src/core/qgsmaprenderersequentialjob.cpp
+++ b/src/core/qgsmaprenderersequentialjob.cpp
@@ -66,7 +66,7 @@ void QgsMapRendererSequentialJob::start()
   mInternalJob = new QgsMapRendererCustomPainterJob( mSettings, mPainter );
   mInternalJob->setCache( mCache );
 
-  connect( mInternalJob, SIGNAL( finished() ), SLOT( internalFinished() ) );
+  connect( mInternalJob, &QgsMapRendererJob::finished, this, &QgsMapRendererSequentialJob::internalFinished );
 
   mInternalJob->start();
 }
diff --git a/src/core/qgsmessagelog.cpp b/src/core/qgsmessagelog.cpp
index a75677c1921..e147e635e93 100644
--- a/src/core/qgsmessagelog.cpp
+++ b/src/core/qgsmessagelog.cpp
@@ -47,8 +47,8 @@ void QgsMessageLog::emitMessage( const QString &message, const QString &tag, Qgs
 QgsMessageLogConsole::QgsMessageLogConsole()
   : QObject( QgsApplication::messageLog() )
 {
-  connect( QgsApplication::messageLog(), SIGNAL( messageReceived( QString, QString, QgsMessageLog::MessageLevel ) ),
-           this, SLOT( logMessage( QString, QString, QgsMessageLog::MessageLevel ) ) );
+  connect( QgsApplication::messageLog(),  static_cast < void ( QgsMessageLog::* )( const QString &, const QString &, QgsMessageLog::MessageLevel ) >( &QgsMessageLog::messageReceived ),
+           this, &QgsMessageLogConsole::logMessage );
 }
 
 void QgsMessageLogConsole::logMessage( const QString &message, const QString &tag, QgsMessageLog::MessageLevel level )
diff --git a/src/core/qgsnetworkaccessmanager.cpp b/src/core/qgsnetworkaccessmanager.cpp
index c41f43ceb3f..dd1ecc775cb 100644
--- a/src/core/qgsnetworkaccessmanager.cpp
+++ b/src/core/qgsnetworkaccessmanager.cpp
@@ -33,6 +33,7 @@
 #include <QTimer>
 #include <QNetworkReply>
 #include <QThreadStorage>
+#include <QAuthenticator>
 
 #ifndef QT_NO_SSL
 #include <QSslConfiguration>
@@ -214,13 +215,13 @@ QNetworkReply *QgsNetworkAccessManager::createRequest( QNetworkAccessManager::Op
   // uploadProgress.
   QTimer *timer = new QTimer( reply );
   timer->setObjectName( QStringLiteral( "timeoutTimer" ) );
-  connect( timer, SIGNAL( timeout() ), this, SLOT( abortRequest() ) );
+  connect( timer, &QTimer::timeout, this, &QgsNetworkAccessManager::abortRequest );
   timer->setSingleShot( true );
   timer->start( s.value( QStringLiteral( "/qgis/networkAndProxy/networkTimeout" ), "60000" ).toInt() );
 
-  connect( reply, SIGNAL( downloadProgress( qint64, qint64 ) ), timer, SLOT( start() ) );
-  connect( reply, SIGNAL( uploadProgress( qint64, qint64 ) ), timer, SLOT( start() ) );
-  connect( reply, SIGNAL( finished( ) ), timer, SLOT( stop( ) ) );
+  connect( reply, &QNetworkReply::downloadProgress, timer, [timer] { timer->start(); } );
+  connect( reply, &QNetworkReply::uploadProgress, timer, [timer] { timer->start(); } );
+  connect( reply, &QNetworkReply::finished, timer, &QTimer::stop );
   QgsDebugMsgLevel( QString( "Created [reply:%1]" ).arg( ( qint64 ) reply, 0, 16 ), 3 );
 
   return reply;
@@ -291,20 +292,20 @@ void QgsNetworkAccessManager::setupDefaultProxyAndCache()
 
   if ( sMainNAM != this )
   {
-    connect( this, SIGNAL( authenticationRequired( QNetworkReply *, QAuthenticator * ) ),
-             sMainNAM, SIGNAL( authenticationRequired( QNetworkReply *, QAuthenticator * ) ),
+    connect( this, &QNetworkAccessManager::authenticationRequired,
+             sMainNAM, &QNetworkAccessManager::authenticationRequired,
              Qt::BlockingQueuedConnection );
 
-    connect( this, SIGNAL( proxyAuthenticationRequired( const QNetworkProxy &, QAuthenticator * ) ),
-             sMainNAM, SIGNAL( proxyAuthenticationRequired( const QNetworkProxy &, QAuthenticator * ) ),
+    connect( this, &QNetworkAccessManager::proxyAuthenticationRequired,
+             sMainNAM, &QNetworkAccessManager::proxyAuthenticationRequired,
              Qt::BlockingQueuedConnection );
 
-    connect( this, SIGNAL( requestTimedOut( QNetworkReply * ) ),
-             sMainNAM, SIGNAL( requestTimedOut( QNetworkReply * ) ) );
+    connect( this, &QgsNetworkAccessManager::requestTimedOut,
+             sMainNAM, &QgsNetworkAccessManager::requestTimedOut );
 
 #ifndef QT_NO_SSL
-    connect( this, SIGNAL( sslErrors( QNetworkReply *, const QList<QSslError> & ) ),
-             sMainNAM, SIGNAL( sslErrors( QNetworkReply *, const QList<QSslError> & ) ),
+    connect( this, &QNetworkAccessManager::sslErrors,
+             sMainNAM, &QNetworkAccessManager::sslErrors,
              Qt::BlockingQueuedConnection );
 #endif
   }
diff --git a/src/core/qgsnetworkcontentfetcher.cpp b/src/core/qgsnetworkcontentfetcher.cpp
index 283e816f59e..6cb1453a3b2 100644
--- a/src/core/qgsnetworkcontentfetcher.cpp
+++ b/src/core/qgsnetworkcontentfetcher.cpp
@@ -59,7 +59,7 @@ void QgsNetworkContentFetcher::fetchContent( const QUrl &url )
   }
 
   mReply = QgsNetworkAccessManager::instance()->get( request );
-  connect( mReply, SIGNAL( finished() ), this, SLOT( contentLoaded() ) );
+  connect( mReply, &QNetworkReply::finished, this, [ = ] { contentLoaded(); } );
 }
 
 QNetworkReply *QgsNetworkContentFetcher::reply()
diff --git a/src/core/qgsofflineediting.cpp b/src/core/qgsofflineediting.cpp
index 111da773923..4aafa0a03ea 100644
--- a/src/core/qgsofflineediting.cpp
+++ b/src/core/qgsofflineediting.cpp
@@ -59,7 +59,7 @@ extern "C"
 
 QgsOfflineEditing::QgsOfflineEditing()
 {
-  connect( QgsProject::instance(), SIGNAL( layerWasAdded( QgsMapLayer * ) ), this, SLOT( layerAdded( QgsMapLayer * ) ) );
+  connect( QgsProject::instance(), &QgsProject::layerWasAdded, this, &QgsOfflineEditing::layerAdded );
 }
 
 /**
@@ -1372,17 +1372,18 @@ void QgsOfflineEditing::startListenFeatureChanges()
   // enable logging, check if editBuffer is not null
   if ( vLayer->editBuffer() )
   {
-    connect( vLayer->editBuffer(), SIGNAL( committedAttributesAdded( const QString &, const QList<QgsField> & ) ),
-             this, SLOT( committedAttributesAdded( const QString &, const QList<QgsField> & ) ) );
-    connect( vLayer->editBuffer(), SIGNAL( committedAttributeValuesChanges( const QString &, const QgsChangedAttributesMap & ) ),
-             this, SLOT( committedAttributeValuesChanges( const QString &, const QgsChangedAttributesMap & ) ) );
-    connect( vLayer->editBuffer(), SIGNAL( committedGeometriesChanges( const QString &, const QgsGeometryMap & ) ),
-             this, SLOT( committedGeometriesChanges( const QString &, const QgsGeometryMap & ) ) );
+    QgsVectorLayerEditBuffer *editBuffer = vLayer->editBuffer();
+    connect( editBuffer, &QgsVectorLayerEditBuffer::committedAttributesAdded,
+             this, &QgsOfflineEditing::committedAttributesAdded );
+    connect( editBuffer, &QgsVectorLayerEditBuffer::committedAttributeValuesChanges,
+             this, &QgsOfflineEditing::committedAttributeValuesChanges );
+    connect( editBuffer, &QgsVectorLayerEditBuffer::committedGeometriesChanges,
+             this, &QgsOfflineEditing::committedGeometriesChanges );
   }
-  connect( vLayer, SIGNAL( committedFeaturesAdded( const QString &, const QgsFeatureList & ) ),
-           this, SLOT( committedFeaturesAdded( const QString &, const QgsFeatureList & ) ) );
-  connect( vLayer, SIGNAL( committedFeaturesRemoved( const QString &, const QgsFeatureIds & ) ),
-           this, SLOT( committedFeaturesRemoved( const QString &, const QgsFeatureIds & ) ) );
+  connect( vLayer, &QgsVectorLayer::committedFeaturesAdded,
+           this, &QgsOfflineEditing::committedFeaturesAdded );
+  connect( vLayer, &QgsVectorLayer::committedFeaturesRemoved,
+           this, &QgsOfflineEditing::committedFeaturesRemoved );
 }
 
 void QgsOfflineEditing::stopListenFeatureChanges()
@@ -1391,17 +1392,18 @@ void QgsOfflineEditing::stopListenFeatureChanges()
   // disable logging, check if editBuffer is not null
   if ( vLayer->editBuffer() )
   {
-    disconnect( vLayer->editBuffer(), SIGNAL( committedAttributesAdded( const QString &, const QList<QgsField> & ) ),
-                this, SLOT( committedAttributesAdded( const QString &, const QList<QgsField> & ) ) );
-    disconnect( vLayer->editBuffer(), SIGNAL( committedAttributeValuesChanges( const QString &, const QgsChangedAttributesMap & ) ),
-                this, SLOT( committedAttributeValuesChanges( const QString &, const QgsChangedAttributesMap & ) ) );
-    disconnect( vLayer->editBuffer(), SIGNAL( committedGeometriesChanges( const QString &, const QgsGeometryMap & ) ),
-                this, SLOT( committedGeometriesChanges( const QString &, const QgsGeometryMap & ) ) );
+    QgsVectorLayerEditBuffer *editBuffer = vLayer->editBuffer();
+    disconnect( editBuffer, &QgsVectorLayerEditBuffer::committedAttributesAdded,
+                this, &QgsOfflineEditing::committedAttributesAdded );
+    disconnect( editBuffer, &QgsVectorLayerEditBuffer::committedAttributeValuesChanges,
+                this, &QgsOfflineEditing::committedAttributeValuesChanges );
+    disconnect( editBuffer, &QgsVectorLayerEditBuffer::committedGeometriesChanges,
+                this, &QgsOfflineEditing::committedGeometriesChanges );
   }
-  disconnect( vLayer, SIGNAL( committedFeaturesAdded( const QString &, const QgsFeatureList & ) ),
-              this, SLOT( committedFeaturesAdded( const QString &, const QgsFeatureList & ) ) );
-  disconnect( vLayer, SIGNAL( committedFeaturesRemoved( const QString &, const QgsFeatureIds & ) ),
-              this, SLOT( committedFeaturesRemoved( const QString &, const QgsFeatureIds & ) ) );
+  disconnect( vLayer, &QgsVectorLayer::committedFeaturesAdded,
+              this, &QgsOfflineEditing::committedFeaturesAdded );
+  disconnect( vLayer, &QgsVectorLayer::committedFeaturesRemoved,
+              this, &QgsOfflineEditing::committedFeaturesRemoved );
 }
 
 void QgsOfflineEditing::layerAdded( QgsMapLayer *layer )
@@ -1410,8 +1412,8 @@ void QgsOfflineEditing::layerAdded( QgsMapLayer *layer )
   if ( layer->customProperty( CUSTOM_PROPERTY_IS_OFFLINE_EDITABLE, false ).toBool() )
   {
     QgsVectorLayer *vLayer = qobject_cast<QgsVectorLayer *>( layer );
-    connect( vLayer, SIGNAL( editingStarted() ), this, SLOT( startListenFeatureChanges() ) );
-    connect( vLayer, SIGNAL( editingStopped() ), this, SLOT( stopListenFeatureChanges() ) );
+    connect( vLayer, &QgsVectorLayer::editingStarted, this, &QgsOfflineEditing::startListenFeatureChanges );
+    connect( vLayer, &QgsVectorLayer::editingStopped, this, &QgsOfflineEditing::stopListenFeatureChanges );
   }
 }
 
diff --git a/src/core/qgspointlocator.cpp b/src/core/qgspointlocator.cpp
index 2518d557dbb..f6b63186806 100644
--- a/src/core/qgspointlocator.cpp
+++ b/src/core/qgspointlocator.cpp
@@ -629,9 +629,9 @@ QgsPointLocator::QgsPointLocator( QgsVectorLayer *layer, const QgsCoordinateRefe
 
   mStorage = StorageManager::createNewMemoryStorageManager();
 
-  connect( mLayer, SIGNAL( featureAdded( QgsFeatureId ) ), this, SLOT( onFeatureAdded( QgsFeatureId ) ) );
-  connect( mLayer, SIGNAL( featureDeleted( QgsFeatureId ) ), this, SLOT( onFeatureDeleted( QgsFeatureId ) ) );
-  connect( mLayer, SIGNAL( geometryChanged( QgsFeatureId, const QgsGeometry & ) ), this, SLOT( onGeometryChanged( QgsFeatureId, const QgsGeometry & ) ) );
+  connect( mLayer, &QgsVectorLayer::featureAdded, this, &QgsPointLocator::onFeatureAdded );
+  connect( mLayer, &QgsVectorLayer::featureDeleted, this, &QgsPointLocator::onFeatureDeleted );
+  connect( mLayer, &QgsVectorLayer::geometryChanged, this, &QgsPointLocator::onGeometryChanged );
   connect( mLayer, &QgsVectorLayer::dataChanged, this, &QgsPointLocator::destroyIndex );
 }
 
diff --git a/src/core/qgsproject.cpp b/src/core/qgsproject.cpp
index b2ac9c14d50..0a9cd18a878 100644
--- a/src/core/qgsproject.cpp
+++ b/src/core/qgsproject.cpp
@@ -339,9 +339,9 @@ QgsProject::QgsProject( QObject *parent )
   // whenever layers are added to or removed from the registry,
   // layer tree will be updated
   mLayerTreeRegistryBridge = new QgsLayerTreeRegistryBridge( mRootGroup, this, this );
-  connect( this, SIGNAL( layersAdded( QList<QgsMapLayer *> ) ), this, SLOT( onMapLayersAdded( QList<QgsMapLayer *> ) ) );
-  connect( this, SIGNAL( layersRemoved( QStringList ) ), this, SLOT( cleanTransactionGroups() ) );
-  connect( this, SIGNAL( layersWillBeRemoved( QList<QgsMapLayer *> ) ), this, SLOT( onMapLayersRemoved( QList<QgsMapLayer *> ) ) );
+  connect( this, &QgsProject::layersAdded, this, &QgsProject::onMapLayersAdded );
+  connect( this, &QgsProject::layersRemoved, this, [ = ] { cleanTransactionGroups(); } );
+  connect( this, static_cast < void ( QgsProject::* )( const QList<QgsMapLayer *> & ) >( &QgsProject::layersWillBeRemoved ), this, &QgsProject::onMapLayersRemoved );
 }
 
 
@@ -1130,7 +1130,7 @@ void QgsProject::onMapLayersAdded( const QList<QgsMapLayer *> &layers )
     if ( tgChanged )
       emit transactionGroupsChanged();
 
-    connect( layer, SIGNAL( configChanged() ), this, SLOT( setDirty() ) );
+    connect( layer, &QgsMapLayer::configChanged, this, [ = ] { setDirty(); } );
 
     // check if we have to update connections for layers with dependencies
     for ( QMap<QString, QgsMapLayer *>::iterator it = existingMaps.begin(); it != existingMaps.end(); it++ )
@@ -2128,7 +2128,7 @@ QList<QgsMapLayer *> QgsProject::addMapLayers(
       {
         myLayer->setParent( this );
       }
-      connect( myLayer, SIGNAL( destroyed( QObject * ) ), this, SLOT( onMapLayerDeleted( QObject * ) ) );
+      connect( myLayer, &QObject::destroyed, this, &QgsProject::onMapLayerDeleted );
       emit layerWasAdded( myLayer );
     }
   }
diff --git a/src/core/qgsrelationmanager.cpp b/src/core/qgsrelationmanager.cpp
index ba11855186a..6c79784ccc8 100644
--- a/src/core/qgsrelationmanager.cpp
+++ b/src/core/qgsrelationmanager.cpp
@@ -25,9 +25,9 @@ QgsRelationManager::QgsRelationManager( QgsProject *project )
   : QObject( project )
   , mProject( project )
 {
-  connect( project, SIGNAL( readProject( const QDomDocument & ) ), SLOT( readProject( const QDomDocument & ) ) );
-  connect( project, SIGNAL( writeProject( QDomDocument & ) ), SLOT( writeProject( QDomDocument & ) ) );
-  connect( project, SIGNAL( layersRemoved( QStringList ) ), this, SLOT( layersRemoved( QStringList ) ) );
+  connect( project, &QgsProject::readProject, this, &QgsRelationManager::readProject );
+  connect( project, &QgsProject::writeProject, this, &QgsRelationManager::writeProject );
+  connect( project, &QgsProject::layersRemoved, this, &QgsRelationManager::layersRemoved );
 }
 
 void QgsRelationManager::setRelations( const QList<QgsRelation> &relations )
diff --git a/src/core/qgsrunprocess.cpp b/src/core/qgsrunprocess.cpp
index 7d98414762c..2b31a6822d2 100644
--- a/src/core/qgsrunprocess.cpp
+++ b/src/core/qgsrunprocess.cpp
@@ -40,13 +40,13 @@ QgsRunProcess::QgsRunProcess( const QString &action, bool capture )
 
   if ( capture )
   {
-    connect( mProcess, SIGNAL( error( QProcess::ProcessError ) ), this, SLOT( processError( QProcess::ProcessError ) ) );
-    connect( mProcess, SIGNAL( readyReadStandardOutput() ), this, SLOT( stdoutAvailable() ) );
-    connect( mProcess, SIGNAL( readyReadStandardError() ), this, SLOT( stderrAvailable() ) );
+    connect( mProcess, static_cast < void ( QProcess::* )( QProcess::ProcessError ) >( &QProcess::error ), this, &QgsRunProcess::processError );
+    connect( mProcess, &QProcess::readyReadStandardOutput, this, &QgsRunProcess::stdoutAvailable );
+    connect( mProcess, &QProcess::readyReadStandardError, this, &QgsRunProcess::stderrAvailable );
     // We only care if the process has finished if we are capturing
     // the output from the process, hence this connect() call is
     // inside the capture if() statement.
-    connect( mProcess, SIGNAL( finished( int, QProcess::ExitStatus ) ), this, SLOT( processExit( int, QProcess::ExitStatus ) ) );
+    connect( mProcess, static_cast < void ( QProcess::* )( int,  QProcess::ExitStatus ) >( &QProcess::finished ), this, &QgsRunProcess::processExit );
 
     // Use QgsMessageOutput for displaying output to user
     // It will delete itself when the dialog box is closed.
@@ -59,7 +59,7 @@ QgsRunProcess::QgsRunProcess( const QString &action, bool capture )
     QObject *mOutputObj = dynamic_cast<QObject *>( mOutput );
     if ( mOutputObj )
     {
-      connect( mOutputObj, SIGNAL( destroyed() ), this, SLOT( dialogGone() ) );
+      connect( mOutputObj, &QObject::destroyed, this, &QgsRunProcess::dialogGone );
     }
 
     // start the process!
@@ -141,10 +141,10 @@ void QgsRunProcess::dialogGone()
 
   mOutput = nullptr;
 
-  disconnect( mProcess, SIGNAL( error( QProcess::ProcessError ) ), this, SLOT( processError( QProcess::ProcessError ) ) );
-  disconnect( mProcess, SIGNAL( readyReadStandardOutput() ), this, SLOT( stdoutAvailable() ) );
-  disconnect( mProcess, SIGNAL( readyReadStandardError() ), this, SLOT( stderrAvailable() ) );
-  disconnect( mProcess, SIGNAL( finished( int, QProcess::ExitStatus ) ), this, SLOT( processExit( int, QProcess::ExitStatus ) ) );
+  disconnect( mProcess, static_cast < void ( QProcess::* )( QProcess::ProcessError ) >( &QProcess::error ), this, &QgsRunProcess::processError );
+  disconnect( mProcess, &QProcess::readyReadStandardOutput, this, &QgsRunProcess::stdoutAvailable );
+  disconnect( mProcess, &QProcess::readyReadStandardError, this, &QgsRunProcess::stderrAvailable );
+  disconnect( mProcess, static_cast < void ( QProcess::* )( int, QProcess::ExitStatus ) >( &QProcess::finished ), this, &QgsRunProcess::processExit );
 
   die();
 }
diff --git a/src/core/qgstracer.cpp b/src/core/qgstracer.cpp
index d81e780061a..e0b95973f2a 100644
--- a/src/core/qgstracer.cpp
+++ b/src/core/qgstracer.cpp
@@ -583,20 +583,20 @@ void QgsTracer::setLayers( const QList<QgsVectorLayer *> &layers )
 
   Q_FOREACH ( QgsVectorLayer *layer, mLayers )
   {
-    disconnect( layer, SIGNAL( featureAdded( QgsFeatureId ) ), this, SLOT( onFeatureAdded( QgsFeatureId ) ) );
-    disconnect( layer, SIGNAL( featureDeleted( QgsFeatureId ) ), this, SLOT( onFeatureDeleted( QgsFeatureId ) ) );
-    disconnect( layer, SIGNAL( geometryChanged( QgsFeatureId, const QgsGeometry & ) ), this, SLOT( onGeometryChanged( QgsFeatureId, const QgsGeometry & ) ) );
-    disconnect( layer, SIGNAL( destroyed( QObject * ) ), this, SLOT( onLayerDestroyed( QObject * ) ) );
+    disconnect( layer, &QgsVectorLayer::featureAdded, this, &QgsTracer::onFeatureAdded );
+    disconnect( layer, &QgsVectorLayer::featureDeleted, this, &QgsTracer::onFeatureDeleted );
+    disconnect( layer, &QgsVectorLayer::geometryChanged, this, &QgsTracer::onGeometryChanged );
+    disconnect( layer, &QObject::destroyed, this, &QgsTracer::onLayerDestroyed );
   }
 
   mLayers = layers;
 
   Q_FOREACH ( QgsVectorLayer *layer, mLayers )
   {
-    connect( layer, SIGNAL( featureAdded( QgsFeatureId ) ), this, SLOT( onFeatureAdded( QgsFeatureId ) ) );
-    connect( layer, SIGNAL( featureDeleted( QgsFeatureId ) ), this, SLOT( onFeatureDeleted( QgsFeatureId ) ) );
-    connect( layer, SIGNAL( geometryChanged( QgsFeatureId, const QgsGeometry & ) ), this, SLOT( onGeometryChanged( QgsFeatureId, const QgsGeometry & ) ) );
-    connect( layer, SIGNAL( destroyed( QObject * ) ), this, SLOT( onLayerDestroyed( QObject * ) ) );
+    connect( layer, &QgsVectorLayer::featureAdded, this, &QgsTracer::onFeatureAdded );
+    connect( layer, &QgsVectorLayer::featureDeleted, this, &QgsTracer::onFeatureDeleted );
+    connect( layer, &QgsVectorLayer::geometryChanged, this, &QgsTracer::onGeometryChanged );
+    connect( layer, &QObject::destroyed, this, &QgsTracer::onLayerDestroyed );
   }
 
   invalidateGraph();
diff --git a/src/core/qgstransaction.cpp b/src/core/qgstransaction.cpp
index 25c272a5fd3..677f70c7eb2 100644
--- a/src/core/qgstransaction.cpp
+++ b/src/core/qgstransaction.cpp
@@ -110,7 +110,7 @@ bool QgsTransaction::addLayer( QgsVectorLayer *layer )
   }
 
   connect( this, &QgsTransaction::afterRollback, layer->dataProvider(), &QgsVectorDataProvider::dataChanged );
-  connect( QgsProject::instance(), SIGNAL( layersWillBeRemoved( QStringList ) ), this, SLOT( onLayersDeleted( QStringList ) ) );
+  connect( QgsProject::instance(),  static_cast < void ( QgsProject::* )( const QStringList & ) >( &QgsProject::layersWillBeRemoved ), this, &QgsTransaction::onLayersDeleted );
   mLayers.insert( layer );
 
   if ( mTransactionActive )
diff --git a/tests/src/core/testqgis.cpp b/tests/src/core/testqgis.cpp
index 8b3c20ca16a..24dc7dd4b34 100644
--- a/tests/src/core/testqgis.cpp
+++ b/tests/src/core/testqgis.cpp
@@ -160,7 +160,7 @@ void TestQgis::signalBlocker()
 {
   std::unique_ptr< QCheckBox > checkbox( new QCheckBox() );
 
-  QSignalSpy spy( checkbox.get(), SIGNAL( toggled( bool ) ) );
+  QSignalSpy spy( checkbox.get(), &QCheckBox::toggled );
 
   //first check that signals are not blocked
   QVERIFY( !checkbox->signalsBlocked() );