diff --git a/src/QGCApplication.cc b/src/QGCApplication.cc
index f7922cbd6845b7b370ce1933cb683da24af8fa21..7daafc0fd7691ce25467bd907831c8e4346ef5d3 100644
--- a/src/QGCApplication.cc
+++ b/src/QGCApplication.cc
@@ -434,7 +434,7 @@ bool QGCApplication::_initForNormalAppBoot(void)
     _loadCurrentStyle();
 
     // Exit main application when last window is closed
-    connect(this, SIGNAL(lastWindowClosed()), this, SLOT(quit()));
+    connect(this, &QGCApplication::lastWindowClosed, this, QGCApplication::quit);
 
 #ifdef __mobile__
     _qmlAppEngine = new QQmlApplicationEngine(this);
diff --git a/src/QGCFileDownload.cc b/src/QGCFileDownload.cc
index c92e4f937931dd79b6c9bd211ef148897265f56f..fd6d0e04aa93b737d37ed2655c07d9096989aaa0 100644
--- a/src/QGCFileDownload.cc
+++ b/src/QGCFileDownload.cc
@@ -81,7 +81,8 @@ bool QGCFileDownload::download(const QString& remoteFile)
 
     connect(networkReply, &QNetworkReply::downloadProgress, this, &QGCFileDownload::downloadProgress);
     connect(networkReply, &QNetworkReply::finished, this, &QGCFileDownload::_downloadFinished);
-    connect(networkReply, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(_downloadError(QNetworkReply::NetworkError)));
+    connect(networkReply, static_cast<void (QNetworkReply::*)(QNetworkReply::NetworkError)>(&QNetworkReply::error),
+            this, &QGCFileDownload::_downloadError);
 
     return true;
 }
diff --git a/src/QGCFileDownload.h b/src/QGCFileDownload.h
index 3e9a3833135eb32b4bb387674cc6ff59f01d53c5..45dc758cc38296466b390f510dd003feb806b792 100644
--- a/src/QGCFileDownload.h
+++ b/src/QGCFileDownload.h
@@ -43,7 +43,7 @@ signals:
     void downloadFinished(QString remoteFile, QString localFile);
     void error(QString errorMsg);
 
-private slots:
+private:
     void _downloadFinished(void);
     void _downloadError(QNetworkReply::NetworkError code);
 };
diff --git a/src/QmlControls/QmlObjectListModel.cc b/src/QmlControls/QmlObjectListModel.cc
index 1e510c81f353190298fcc6db6b8ca8367183e6ea..21a5ed72e0b845f3c0f40ba03a4da3ecc6c7a3a8 100644
--- a/src/QmlControls/QmlObjectListModel.cc
+++ b/src/QmlControls/QmlObjectListModel.cc
@@ -151,7 +151,7 @@ void QmlObjectListModel::clear(void)
 QObject* QmlObjectListModel::removeAt(int i)
 {
     QObject* removedObject = _objectList[i];
-    
+
     // Look for a dirtyChanged signal on the object
     if (_objectList[i]->metaObject()->indexOfSignal(QMetaObject::normalizedSignature("dirtyChanged(bool)")) != -1) {
         if (!_skipDirtyFirstItem || i != 0) {
diff --git a/src/QtLocationPlugin/OpenPilotMaps.cc b/src/QtLocationPlugin/OpenPilotMaps.cc
index bacb6b569ec94a08a2bf6fd458024e59baeef372..8816d85269f7195b0acd8a62921dcac6fff9e546 100644
--- a/src/QtLocationPlugin/OpenPilotMaps.cc
+++ b/src/QtLocationPlugin/OpenPilotMaps.cc
@@ -205,9 +205,11 @@ void UrlFactory::_tryCorrectGoogleVersions()
 #endif
         qheader.setRawHeader("User-Agent", userAgent);
         _googleReply = _network->get(qheader);
-        connect(_googleReply, SIGNAL(finished()), this, SLOT(_googleVersionCompleted()));
-        connect(_googleReply, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(_networkReplyError(QNetworkReply::NetworkError)));
-        connect(_googleReply, SIGNAL(destroyed()), this, SLOT(_replyDestroyed()));
+        connect(_googleReply, &QNetworkReply::finished, this, &UrlFactory::_googleVersionCompleted);
+        connect(_googleReply, &QNetworkReply::destroyed, this, &UrlFactory::_replyDestroyed);
+
+        connect(_googleReply, static_cast<void (QNetworkReply::*)(QNetworkReply::NetworkError)>(&QNetworkReply::error),
+                this, &UrlFactory::_networkReplyError);
         _network->setProxy(proxy);
     }
 }