diff --git a/src/app/core/qcommandlineoption.cpp b/src/app/core/qcommandlineoption.cpp
index b0bcd15b0..4c8616353 100644
--- a/src/app/core/qcommandlineoption.cpp
+++ b/src/app/core/qcommandlineoption.cpp
@@ -40,12 +40,17 @@
 **
 ****************************************************************************/
 
-#if QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
-
 #include "qcommandlineoption.h"
 
+#if QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
+
 #include <QSet>
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Weffc++"
+#endif
+
 class QCommandLineOptionPrivate : public QSharedData
 {
 public:
@@ -68,6 +73,10 @@ public:
     QStringList defaultValues;
 };
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic pop
+#endif
+
 /*!
     \since 5.2
     \class QCommandLineOption
diff --git a/src/app/core/qcommandlineoption.h b/src/app/core/qcommandlineoption.h
index 32476e7ee..512430efc 100644
--- a/src/app/core/qcommandlineoption.h
+++ b/src/app/core/qcommandlineoption.h
@@ -42,11 +42,18 @@
 #ifndef QCOMMANDLINEOPTION_H
 #define QCOMMANDLINEOPTION_H
 
+#include <QtGlobal>
+
 #if QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
 
 #include <QStringList>
 #include <QSharedData>
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Weffc++"
+#endif
+
 class QCommandLineOptionPrivate;
 
 class QCommandLineOption
@@ -80,6 +87,10 @@ private:
     QSharedDataPointer<QCommandLineOptionPrivate> d;
 };
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic pop
+#endif
+
 #endif //QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
 
 #endif // QCOMMANDLINEOPTION_H
diff --git a/src/app/core/qcommandlineparser.cpp b/src/app/core/qcommandlineparser.cpp
index 39f6c1fb5..096223c2a 100644
--- a/src/app/core/qcommandlineparser.cpp
+++ b/src/app/core/qcommandlineparser.cpp
@@ -40,10 +40,10 @@
 **
 ****************************************************************************/
 
-#if QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
-
 #include "qcommandlineparser.h"
 
+#if QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
+
 #include <QCoreApplication>
 #include <QHash>
 #include <QVector>
@@ -52,6 +52,13 @@
 
 typedef QHash<QString, int> NameHash_t;
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Weffc++"
+    #pragma GCC diagnostic ignored "-Wswitch-default"
+    #pragma GCC diagnostic ignored "-Wsuggest-attribute=noreturn"
+#endif
+
 class QCommandLineParserPrivate
 {
 public:
@@ -945,4 +952,8 @@ QString QCommandLineParserPrivate::helpText() const
     return text;
 }
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic pop
+#endif
+
 #endif //QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
diff --git a/src/app/core/qcommandlineparser.h b/src/app/core/qcommandlineparser.h
index b7a8f3418..29dbc7e97 100644
--- a/src/app/core/qcommandlineparser.h
+++ b/src/app/core/qcommandlineparser.h
@@ -42,6 +42,8 @@
 #ifndef QCOMMANDLINEPARSER_H
 #define QCOMMANDLINEPARSER_H
 
+#include <QtGlobal>
+
 #if QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
 
 #include <QStringList>
@@ -49,6 +51,11 @@
 
 #include "qcommandlineoption.h"
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic push
+    #pragma GCC diagnostic ignored "-Weffc++"
+#endif
+
 class QCommandLineParserPrivate;
 class QCoreApplication;
 
@@ -101,6 +108,10 @@ private:
     QCommandLineParserPrivate * const d;
 };
 
+#ifdef Q_CC_GNU
+    #pragma GCC diagnostic pop
+#endif
+
 #endif //QT_VERSION < QT_VERSION_CHECK(5, 2, 1)
 
 #endif // QCOMMANDLINEPARSER_H
diff --git a/src/app/dialogs/app/dialogaboutapp.ui b/src/app/dialogs/app/dialogaboutapp.ui
index bf16a0058..b14244843 100644
--- a/src/app/dialogs/app/dialogaboutapp.ui
+++ b/src/app/dialogs/app/dialogaboutapp.ui
@@ -188,9 +188,6 @@
          <property name="horizontalScrollBarPolicy">
           <enum>Qt::ScrollBarAlwaysOff</enum>
          </property>
-         <property name="sizeAdjustPolicy">
-          <enum>QAbstractScrollArea::AdjustToContentsOnFirstShow</enum>
-         </property>
          <property name="autoFormatting">
           <set>QTextEdit::AutoNone</set>
          </property>
diff --git a/src/app/main.cpp b/src/app/main.cpp
index 22a59940c..6294ec7f9 100644
--- a/src/app/main.cpp
+++ b/src/app/main.cpp
@@ -129,7 +129,7 @@ int main(int argc, char *argv[])
     Q_INIT_RESOURCE(schema);
     Q_INIT_RESOURCE(theme);
 
-    QT_REQUIRE_VERSION(argc, argv, "5.2.1");
+    QT_REQUIRE_VERSION(argc, argv, "5.0.2");
 
     VApplication app(argc, argv);
 #ifdef QT_DEBUG