Good idea. It would make the info easier to find.
FYI, it is available now, just in a different location / manner.
In PMS Settings -> General, if an update is available there is a link to a “What’s New” instead of showing “Up to date.”.
You can subscribe to the Plex Media Server announcement thread. You’ll receive an e-mail when the thread is updated. To subscribe, scroll to the bottom of the thread and change status from Normal to Watching.