I fixed the books not showing up thing for myself at least. Uninstall this, and if you're not too attached to your googleplay games account and data, delete it, make new one, reinstall this mod. Books now showing.
The app works fine, but the newest books aren't updating. Can't tell if this is because of the hack or if it's something on their side. Their official pages state they've changed it so you no longer have to update to get the new books. Said to log out and back in and Portia's would be updated...