Software compatible with only one release

Hi. I'm the packager of gnome-shell-extension-weather. Currently I'm packaging the fork by Neroth ( https://github.com/Neroth/gnome-shell-extension-weather ), which is compatible with Gnome versions up to 3.4 (i.e. Fedora up to 17), into the branches F-16, F-17, F-18 and devel. Now, with the release of Fedora 18 approaching, I'd like to switch to the fork by canek-pelaez ( https://github.com/canek-pelaez/gnome-shell-extension-weather ), that is compatible only with Gnome 3.6, i.e Fedora 18. The more obvious choice is packaging the latter into the F-18 and devel branches only and simply leaving the F-16 and F-17 branches unchanged. Is this the right approach? If not, how should I behave? I'd like to hear some opinions from more experienced users. Thank you. Cheers, Mattia M.