@ps67 What NiLuJe linked is work currently being done. You need to wait patiently, till it's finished. If you want to help testing, take a look at
https://github.com/koreader/koreader/issues/6479 and
https://github.com/koreader/koreader/pull/6680 once in a while. You'd have to know how to use git and build the application yourself, then report the results there.