Just "upgraded" - Started with a new clone from AUR, built and installed without issues. Just one observation, when installing, pacman thought I was "downgrading" the existing package, which I'm sure is just because of a syntax difference between the apparent version numbers, and is safe to ignore during this transition.
From pacman.log:
downgraded mythtv (1:31.0-3 -> 31+fixes.20201012.eb3c84de-1)
Pinned Comments
JohnLBergqvist commented on 2023-04-10 15:56 (UTC) (edited on 2023-04-10 15:57 (UTC) by JohnLBergqvist)
This package replaces the previous 'mythtv' AUR package. It has been renamed to comply with Arch's VCS package guidelines.
I hope to update the various mythplugins AUR packages soon