The later I try it seems the less stable (I haven’t tried every version) and timeshift features work little to none based on the version.
8.2.1 is what I’ve had the most success with (recording, starting from the beginning of that recording, and timeshift are all great). Oh, and of course I don’t get kicked out of the stream.
I don’t know if this makes a difference, but I’ve never updated my hdhomerun software. I wonder if Plex changes and tests with the latest hdhomerun software and me being on a 3+ year old version is causing problems. The later Plex gets the more unusable live tv and DVR features become on Android clients. 
Amazon fire I believe would need to sideload Amazon Fire OS Devices (armv7a) 25 from Plex for Android - #348 by SamFromPlex if I am not mistaken (and anyone wants to see how theirs would run on this version).
I don’t live being on such an old version because I feel I might be missing out on other features/fixes but this is the main reason I subscribed to Plex pass years ago.
