Continue Watching and the post-play screen should already consider mid-season specials based on their air date.
As an example:
If you watched Doctor Who (2005) s02e13 (“Doomsday”), Plex won’t suggest to continue with s03e01 but the 2006 X-Mas special instead (“The Runaway Bride”).
Alternatively you can of course create a collection of episodes and configure it to sort the episodes by release date.
- For a regular/classic collection, you can set their order when editing the collection (
Advanced
>Collection order
). - For a smart collection you can specify the search order when creating/editing its filters.
As a side note – there’s an existing feature suggestion asking for an option to display specials inline with an episode based on their air date.