On January 31, 2020, one of the primary sources of TV artwork in your Plex library will be making a configuration change that will prevent any new TV shows added to libraries on older Plex Media Servers from getting artwork.
Starting January 31st, Plex Media Server version 1.18.2 or higher will be required to continue fetching TV show posters and episode thumbnails from TheTVDB.
If you’re currently running an older server version, make sure you grab and install the latest release to keep things running smoothly.
Thanks,
The Plex Team