code specific for Qt < 5.15 removed

README.md

@@ -27,7 +27,7 @@ controls is limited to the needs of the driving projects.
 
 QSkinny is supposed to run on all platforms being supported by Qt/Quick.
 But so far only Linux is actively tested. 
-It might support all versions Qt >= 5.12, but you can rely on:
+It might support all versions Qt >= 5.15, but you can rely on:
 
 - Qt 5.15
 - current long term supported ( LTS ) version of Qt

qmlexport/QskQml.hpp

@@ -7,11 +7,6 @@
 #define QSK_QML_HPP
 
 #include <qqml.h>
-
-#if QT_VERSION < QT_VERSION_CHECK( 5, 14, 0 )
-    #include <qqmlengine.h>
-#endif
-
 #include <ctype.h>
 
 #define QSK_MODULE_NAME "Skinny"
@@ -273,20 +268,8 @@ namespace QskQml
     {
         const auto name = classNameQml( T::staticMetaObject );
 
-#if QT_VERSION < QT_VERSION_CHECK( 5, 14, 0 )
-        auto callback =
-            []( QQmlEngine*, QJSEngine* )
-            {
-                QQmlEngine::setObjectOwnership( singleton, QQmlEngine::CppOwnership );
-                return singleton;
-            };
-
-        return qmlRegisterSingletonType< T >( QSK_MODULE_NAME,
-            QSK_VERSION_MAJOR, QSK_VERSION_MINOR, name, callback );
-#else
         return qmlRegisterSingletonInstance( QSK_MODULE_NAME,
             QSK_VERSION_MAJOR, QSK_VERSION_MINOR, name, singleton );
-#endif
     }
 }
 

src/common/QskMetaFunction.cpp

@@ -55,11 +55,7 @@ int QskMetaFunction::FunctionCall::typeInfo() const
 int QskMetaFunction::FunctionCall::refCount() const
 {
     auto that = const_cast< FunctionCall* >( this );
-#if QT_VERSION >= QT_VERSION_CHECK( 5, 14, 0 )
     return reinterpret_cast< SlotObject* >( that )->ref.loadRelaxed();
-#else
-    return reinterpret_cast< SlotObject* >( that )->ref.load();
-#endif
 }
 
 QskMetaFunction::QskMetaFunction()