I believe I’ve been reading that the hosted version is the “latest and newest” for everybody who wants to go there while the version bundled with your Plex Media Server installation is considered “stable”.
The PMS release notes will have a note if it’ll update the bundled version of Plex Web.
If I haven’t missed an announcement, the last update to the bundled version came with PMS v1.20.0.3125 when Plex Web was update to 4.34.4. The hosted version of Plex Web is v4.44.1
I don’t think there’s a specific predetermined pattern that the bundled version is always 10 minor versions behind… you’ll depend on Plex to decide when they update the bundled version
