I have a friend of mine who has his PMS (0.9.8.6.175-88ffbb2) shared to me. He has his set up to always enabled subtitles. There doesn't appear to be a way for me to watch anything from his server without being able to turn those subtitles off. Is there or will there ever be a way I can have my own subtitle settings? I'm using 0.9.808.201-e10aca1 for my server if that matters.
Are you not able to turn them off just before playing a particular file? (should be a drop down box)
What OS is his server on?
Only possible reason I could think of there being an issue is if he is using it on FreeBSD as that release cannot transcode subtitles.
There isn't any sort of inherent compatility issue with subtitles and sharing that I have ever heard of though.
He's running his server with Debian Wheezy on an i5. I have no option to select subtitles using the Plex/Web interface (as seen below) or on my Roku players.

Haha, I want that! I actually want to force subs!
So this thread is also helpfull for me :)
Early 2021 clean-up: implemented/fixed