The image for Raspberry Pi references 18.04.2 beta1 despite 18.04.2 being out since February. Given the issues of HDMI out (seeing nada) I figured I'd ask why the listed version isn't final... like if it's an accident on the website or something and there's a more bug free 'final' version out there somewhere...
New images for the Raspberry Pi (+ Model 4) are in the works, as far as I know.
The downloads for 32-bit/64-bit computers (i386/amd64) are provided by Canonical's infrastructure, so they are generated by automated systems and tested by our QA Team.
Everything else that Ubuntu MATE supports (Raspberry Pi, GPD Pocket, etc) needs to be generated and tested by hand, which can take a significant amount of @Wimpy's free time. "Beta 1" indicates that Ubuntu MATE's release of the image is considered beta quality, even though on the desktop, 18.04.2 is not in beta.
Point releases like 18.04.2 are like a "snapshot" of updates, so when you update the system, you'll be at 18.04.3. Bearing in mind the Raspberry Pi 18.04 experience in general is still at "Beta 1".
Our project leader will know the answer to this question.