It seems like there should be a post somewhere that simply gets updated when a new version is available. Something simple, wherein a message like "Beta X now available, click here for more info" would be posted. That would mean I could just follow that discussion, and use it to know when updates are available.
Is there another way to know of updates? Right now I have to keep coming back to this forum and search for a "Flarum vX.Y.Z-betaN released" post.