Ah I just switched to using https://github.com/uxjulia/crossink-reader

Not sure what KOReader is but the fonts included in this one and the overall reading experience is solid.

KOReader is the defacto Android ereader app for eink screens, and many consider it the best Android ereader for regular screens too.

Worth mentioning it's not limited to Android! It also runs on Kobos, Kindles, Pocketbooks, etc.

How does it runs in Kindles? Which ones are supported? I'm interested

Not personally familiar with the details, as I don't have any Amazon devices. Sounds like it involves jailbreaking and per-model differences: https://github.com/koreader/koreader/wiki/Installation-on-Ki...

Make sense now thanks

Ah, didn't know that.

agreed and they support non android devices too!