I just made another recent discovery:
- While the page did not mention an Android version, it does mention the use of MediaTek Helio X20, and I did some searching online to come to the conclusion that it may ship with Android 8.1. This is just a guess, though.
- I just saw this update video, and when they tapped to open a book, I see a "Opening book" modal that is a clear indication that it's actually using KOReader for its reader engine, unlike Likebook that I found uses FBReader for its engine, but only after digging into the APK for its home shell.