diff --git a/test/cfg/qt.cpp b/test/cfg/qt.cpp
index 42bcd03e99e..4eec2f6b20d 100644
--- a/test/cfg/qt.cpp
+++ b/test/cfg/qt.cpp
@@ -15,7 +15,6 @@
 #include <QStack>
 #include <QByteArray>
 #include <QList>
-#include <QLinkedList>
 #include <QMap>
 #include <QMultiMap>
 #include <QQueue>
@@ -34,6 +33,11 @@
 #include <QRegion>
 #include <QTransform>
 
+// TODO: this is actually avilable via Core5Compat but I could not get it to work with pkg-config
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
+#include <QLinkedList>
+#endif
+
 #include <cstdio>
 
 int ignoredReturnValue_QSize_height(const QSize &s)
@@ -323,6 +327,7 @@ QList<int>::iterator QList3()
     return it;
 }
 
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
 void QLinkedList1()
 {
     // cppcheck-suppress unreadVariable
@@ -359,6 +364,7 @@ QLinkedList<int>::iterator QLinkedList3()
     // cppcheck-suppress returnDanglingLifetime
     return it;
 }
+#endif
 
 void QStringList1(QStringList stringlistArg)
 {
@@ -569,11 +575,13 @@ void MacroTest2_test()
     QByteArray ba = str.toLatin1();
     printf(ba.data());
 
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
 #ifndef QT_NO_DEPRECATED
     str = MacroTest2::trUtf8("test2");
     ba = str.toLatin1();
     printf(ba.data());
 #endif
+#endif
 }
 
 void MacroTest3()
@@ -617,7 +625,7 @@ void validCode(int * pIntPtr, QString & qstrArg, double d)
         if (qstr1.length() == 1) {}
     }
     if (qstr1.length() == 1) {} else {
-        qstr1.remove(1);
+        qstr1.remove(1, 0);
         if (qstr1.length() == 1) {}
     }
 }
diff --git a/test/cfg/runtests.sh b/test/cfg/runtests.sh
index c1083d4e769..f6094a62651 100755
--- a/test/cfg/runtests.sh
+++ b/test/cfg/runtests.sh
@@ -107,10 +107,17 @@ function gnu_fn {
 # qt.cpp
 function qt_fn {
     if [ $HAS_PKG_CONFIG -eq 1 ]; then
-        QTCONFIG=$(get_pkg_config_cflags Qt5Core Qt5Test Qt5Gui)
+        # TODO: check syntax with Qt5 and Qt6?
+        QTCONFIG=$(get_pkg_config_cflags Qt6Core Qt6Test Qt6Gui)
+        if [ -z "$QTCONFIG" ]; then
+          QTCONFIG=$(get_pkg_config_cflags Qt5Core Qt5Test Qt5Gui)
+          QTBUILDCONFIG=$(pkg-config --variable=qt_config Qt5Core Qt5Test Qt5Gui)
+          [[ $QTBUILDCONFIG =~ (^|[[:space:]])reduce_relocations($|[[:space:]]) ]] && QTCONFIG="${QTCONFIG} -fPIC"
+        else
+          QTBUILDCONFIG=$(pkg-config --variable=qt_config Qt6Core Qt6Test Qt6Gui)
+          QTCONFIG="${QTCONFIG} -fPIC"
+        fi
         if [ -n "$QTCONFIG" ]; then
-            QTBUILDCONFIG=$(pkg-config --variable=qt_config Qt5Core Qt5Test Qt5Gui)
-            [[ $QTBUILDCONFIG =~ (^|[[:space:]])reduce_relocations($|[[:space:]]) ]] && QTCONFIG="${QTCONFIG} -fPIC"
             # TODO: get rid of the error enabling/disabling?
             set +e
             echo -e "#include <QString>" | ${CXX} "${CXX_OPT[@]}" ${QTCONFIG} -x c++ -