Ok, I upgraded to 17.04 again and got my BT mouse working.
After dist-upgrade before restart, I did not enable DRM and run the commands to update kernel, uboot and package to 0.7.3 just for the cause.
After restart I was not able to connect to mouse, modprobe btusb gave an error. After another update I was able to pair my mouse.
edit: after installing kubuntu-desktop and switching to Plasma I could not login, there was just a blinking blank screen and nothing worked. I just saw a console for a few seconds after pressing crtl+alt+f1, but was not able to login because the display was just blinking. So another try today.
After dist-upgrade before restart, I did not enable DRM and run the commands to update kernel, uboot and package to 0.7.3 just for the cause.
After restart I was not able to connect to mouse, modprobe btusb gave an error. After another update I was able to pair my mouse.
edit: after installing kubuntu-desktop and switching to Plasma I could not login, there was just a blinking blank screen and nothing worked. I just saw a console for a few seconds after pressing crtl+alt+f1, but was not able to login because the display was just blinking. So another try today.