@rogerinnyc: Anything that tries to affect the chrome has been broken since FW 5.6.5.
Other intrusive stuff might not work (or be downright dangerous, cf.
https://www.mobileread.com/forums/sho...d.php?t=270648, but then that one always was a terrible idea to begin with ;p). But barring that, anything with PW2 support should be mostly okay. Might not work, but if it's not intrusive, won't wreak havoc.