There are some other devs working on a fork of plex-for-kodi: https://github.com/pannal/plex-for-kodi/commits/develop
The most recent updates seem to have added better Collections support and Browsing by Folder support, which is pretty great. I’ve not tested it myself yet as I tried a version from about 5 weeks ago and unfortunately seeking was completely broken (on the latest Kodi on my Bravia TV).
You have to install by Zip in order to overwrite the old Plex plugin. Rolling back to the old version is easily done by installing again from the official Kodi repo (retains settings). Would be interested to hear others experience.
