Request #6360 has been rejected by Dragonlord [1]: I'd say wmail-bin should be kept on the latest stable release (currently v1.3.1), wmail-bin-git should be rewritten to use the latest git master and the pre-release versions might be installed via a possible new package wmail-bin-pre I won't be accepting this request for now.
[1] https://aur.archlinux.org/account/Dragonlord/
