Well, I don't know why sergey don't post anything about the new build of pbchess/coolreader in this forum. The new version is 2020.03.26 for kobo (same as kindle 2020.03.27) with support for all newest kobo models.
They can be downloaded from his
web page
Here is my spanish translation for the last build of pbchess 2020.03.xx
You only need to copy and overwrite each file over vlasovsoft directory.