diff --git a/kmail/editorplugins/insertshorturl/shorturlengineplugin/isgdshorturlengineplugin/isgdshorturlengineinterface.cpp b/kmail/editorplugins/insertshorturl/shorturlengineplugin/isgdshorturlengineplugin/isgdshorturlengineinterface.cpp
index c7710523d7102e41b178a5b218b87a877a642953..b5b7d93f5252a909a3c9d9a04e622736ebe06055 100644
--- a/kmail/editorplugins/insertshorturl/shorturlengineplugin/isgdshorturlengineplugin/isgdshorturlengineinterface.cpp
+++ b/kmail/editorplugins/insertshorturl/shorturlengineplugin/isgdshorturlengineplugin/isgdshorturlengineinterface.cpp
@@ -35,7 +35,11 @@ void IsgdShortUrlEngineInterface::generateShortUrl()
 
     request.setHeader(QNetworkRequest::ContentTypeHeader, QStringLiteral("application/json"));
     QNetworkReply *reply = mNetworkAccessManager->get(request);
+#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
     connect(reply, qOverload<QNetworkReply::NetworkError>(&QNetworkReply::error), this, &IsgdShortUrlEngineInterface::slotErrorFound);
+#else
+    connect(reply, qOverload<QNetworkReply::NetworkError>(&QNetworkReply::errorOccurred), this, &IsgdShortUrlEngineInterface::slotErrorFound);
+#endif
 }
 
 void IsgdShortUrlEngineInterface::slotSslErrors(QNetworkReply *reply, const QList<QSslError> &error)
diff --git a/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.cpp b/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.cpp
index a4f236371b3a2827eacc5f5297fbd337317b788a..27145e74d3ef599b0b0bfca7af2137861dc6c5d5 100644
--- a/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.cpp
+++ b/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.cpp
@@ -13,7 +13,6 @@
 
 ShortUrlEngineInterface::ShortUrlEngineInterface(ShortUrlEnginePlugin *plugin, QObject *parent)
     : QObject(parent)
-    , mErrorFound(false)
     , mNetworkAccessManager(new QNetworkAccessManager(this))
     , mEnginePlugin(plugin)
 {
diff --git a/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.h b/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.h
index 90fbb96a3af04f4bcb17543d3398ff22e513e17d..c827a892f3e021df8dde0ee3b05dd143ac90cc74 100644
--- a/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.h
+++ b/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlengineinterface.h
@@ -36,7 +36,7 @@ protected:
     QString mOriginalUrl;
     QTextCursor mTextCursor;
     bool mErrorFound = false;
-    QNetworkAccessManager *mNetworkAccessManager = nullptr;
-    ShortUrlEnginePlugin *mEnginePlugin = nullptr;
+    QNetworkAccessManager *const mNetworkAccessManager;
+    ShortUrlEnginePlugin *const mEnginePlugin;
 };
 #endif // SHORTURLENGINEINTERFACE_H
diff --git a/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlenginepluginmanager.cpp b/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlenginepluginmanager.cpp
index 967efabf3f2f2e845e019472d0d960f677ac9ff7..3e9616f5c3ac8bb5786e412777fdc359545a9f85 100644
--- a/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlenginepluginmanager.cpp
+++ b/kmail/editorplugins/insertshorturl/shorturlengineplugin/shorturlenginepluginmanager.cpp
@@ -17,10 +17,6 @@
 class ShortUrlEnginePluginInfo
 {
 public:
-    ShortUrlEnginePluginInfo()
-        : plugin(nullptr)
-    {
-    }
 
     QString metaDataFileNameBaseName;
     QString metaDataFileName;
@@ -40,7 +36,7 @@ public:
     void loadPlugin(ShortUrlEnginePluginInfo *item);
     QVector<ShortUrlEnginePlugin *> pluginsList() const;
     QVector<ShortUrlEnginePluginInfo> mPluginList;
-    ShortUrlEnginePluginManager *q;
+    ShortUrlEnginePluginManager *const q;
 };
 
 void ShortUrlEnginePluginManagerPrivate::initializePlugins()
diff --git a/kmail/editorplugins/insertshorturl/shorturlengineplugin/tinyurlengineplugin/tinyurlengineinterface.cpp b/kmail/editorplugins/insertshorturl/shorturlengineplugin/tinyurlengineplugin/tinyurlengineinterface.cpp
index f11d2e68c5c53144adaaf44226b3d891a2645336..4b069a1698188e4b13af6ab4a506dc173a130ce0 100644
--- a/kmail/editorplugins/insertshorturl/shorturlengineplugin/tinyurlengineplugin/tinyurlengineinterface.cpp
+++ b/kmail/editorplugins/insertshorturl/shorturlengineplugin/tinyurlengineplugin/tinyurlengineinterface.cpp
@@ -29,7 +29,11 @@ void TinyUrlEngineInterface::generateShortUrl()
 {
     const QString requestUrl = QStringLiteral("https://tinyurl.com/api-create.php?url=%1").arg(mOriginalUrl);
     QNetworkReply *reply = mNetworkAccessManager->get(QNetworkRequest(QUrl(requestUrl)));
+#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
     connect(reply, qOverload<QNetworkReply::NetworkError>(&QNetworkReply::error), this, &TinyUrlEngineInterface::slotErrorFound);
+#else
+    connect(reply, qOverload<QNetworkReply::NetworkError>(&QNetworkReply::errorOccurred), this, &TinyUrlEngineInterface::slotErrorFound);
+#endif
 }
 
 void TinyUrlEngineInterface::slotShortUrlFinished(QNetworkReply *reply)
diff --git a/kmail/editorplugins/insertshorturl/shorturlengineplugin/triopabshorturlengineplugin/triopabshorturlengineinterface.cpp b/kmail/editorplugins/insertshorturl/shorturlengineplugin/triopabshorturlengineplugin/triopabshorturlengineinterface.cpp
index 8050ae2d0370dbaadce545a129daf2c622beaddc..a4b172f4fdca60432be7eb988de5db87b38cab97 100644
--- a/kmail/editorplugins/insertshorturl/shorturlengineplugin/triopabshorturlengineplugin/triopabshorturlengineinterface.cpp
+++ b/kmail/editorplugins/insertshorturl/shorturlengineplugin/triopabshorturlengineplugin/triopabshorturlengineinterface.cpp
@@ -29,7 +29,11 @@ void TripAbShortUrlEngineInterface::generateShortUrl()
 {
     const QString requestUrl = QStringLiteral("https://to.ly/api.php?longurl=%1").arg(mOriginalUrl);
     QNetworkReply *reply = mNetworkAccessManager->get(QNetworkRequest(QUrl(requestUrl)));
+#if QT_VERSION < QT_VERSION_CHECK(5, 15, 0)
     connect(reply, qOverload<QNetworkReply::NetworkError>(&QNetworkReply::error), this, &TripAbShortUrlEngineInterface::slotErrorFound);
+#else
+    connect(reply, qOverload<QNetworkReply::NetworkError>(&QNetworkReply::errorOccurred), this, &TripAbShortUrlEngineInterface::slotErrorFound);
+#endif
 }
 
 void TripAbShortUrlEngineInterface::slotShortUrlFinished(QNetworkReply *reply)