You can always find the latest release notes in this announcement thread. If you “bookmark” the thread (using the forum “bookmark” button… not the browser feature), you can get a notification if there’s a new release (incl. its details).
Upgrading your libraries isn’t specifically linked to the recent server update. This will update existing libraries to use the current generation Plex agents (namely: Plex Movie, Plex TV Series and Plex Music). Existing metadata and customizations shouldn’t be modified by that.
If you’re relying on 3rd party / complementary agents you might not want to upgrade as the new agents no longer support those complementary agents (e.g. opensubtitles.org w/ automatic subtitle download).
