Upgraded my Mini from 3.16 to 3.17 (inkl. disablesickel), no factory reset, partial upgrade via Kobo Start Menu:
=> Ghosting is the same, i.e. strong ghosting for pop up menus like highlighting menu, but no ghosting elsewhere
=> No problems otherwise.
Page turns feel a bit slower, though, but this can be due to increased device temperature
We have 38C right now and my brain is already throttling down....