I currently maintain lib32-allegro  in its version 5.0. However, I wanted to change its version to 4 (anything less than version5) and add a lib32-allegro5 (anything >=5). The idea is to follow packages allegro  and allegro5 . I found a variable "epoch", which if not set in PKGBUILD is equal 0. I could set "epoch=1" to force downgrade to lib32-allegro during the system update and upload to AUR lib32-allegro5 for who wants it.
What do you think about this procedure? Any other suggestions?
Thanks in advance!
 https://aur.archlinux.org/packages.php?ID=20892  http://www.archlinux.org/packages/?sort=&q=allegro&maintainer=&l...  https://aur.archlinux.org/packages.php?ID=23012  https://wiki.archlinux.org/index.php/PKGBUILD#epoch