Would be nice, if it happens: Still a _lot_ to improve on NeoReader and Note.
Looking at the kreader2-release.apk* in the app folder on the system partition, I don't see a lot that is necessarily android 6 dependent.
So if the upgrade doesn't reach the android6 devices even in december, would anyone be willing to share the new apk-file? If it doesn't install without problems, I'll hack it to fit.
After installing
Total Commander, you're free to browse the whole directory structure and I would guess that it's in the root>app>kreader-releaseX directory.
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*When I clicked to install this one with Total Commander, I got the message that NeoReader was already installed. So it's safe to assume that this is the name of the apk-file of NeoReader.