I'm on iOS Plex Version 4.2 on iOS 9.3.2 with PlexServer 126.96.36.1991 and I'm having issues when I try to seek through video content. What happens when I play anything video related I get a "Playback was terminated by the server - Client stopped playback." message. It looks like it doesn't give enough time for the server to seek through the file to get to the desired position. I have a samsung bluray player which seeks with no issues on the same files so I presume it is an iOS issue (unless it is a transcoder issue - in which case I guess I might be in the wrong subforum haha).