SP 831 crashes only when trying to select a mesh because of qt library conflict

The program starts and i can load old *.spp and work with them, Only when i try to select a mesh in existing projects or new it crashes with this last line in log:

[ ERR] <Qt> Cannot mix incompatible Qt library (5.15.1) with this library (5.15.8)

The last time it worked normal is a month ago and since then i only updated the gpu-driver which i already rolled back and reinstalled SP.

How can i even clean up the qt-library conflict, which doesn´t seem to be just one google search away?