Yes, my idea is to package the new fork ( https://github.com/canek-pelaez/gnome-shell-extension-weather , compatible only with Gnome 3.6) into the "F-18" and "devel" branches and keep the old one ( https://github.com/Neroth/gnome-shell-extension-weather , compatible with Gnome up to 3.4) into the "F-16" and "F-17".
By the way, which problems are you talking about? 

2012/10/23 Nicolas Chauvet <kwizart@gmail.com>
Hi Mattia,

You can only package the new fork in F-18 and later.
But it will lead to a problem if you cannot maintain this fork for the
whole F-18 lifetime.

But F-16 and F-17 are still supposed to be maintained, and if the
software doesn't work well, it is expected that it is fix.
I can also be a previous fork on the software.

Thx

Nicolas (kwizart)

2012/10/21 M.M. <hal8600@hotmail.it>:
> Thanks, but my question is: is it enough to just package the new fork into
> the F-18 and devel branches and leave the previous ones unchanged and out-of
> date?
>
> 2012/10/20 Ken Dreyer <ktdreyer@ktdreyer.com>
>>
>> On Sat, Oct 20, 2012 at 1:59 PM, M.M. <hal8600@hotmail.it> wrote:
>> > branches only and simply leaving the F-16 and F-17 branches unchanged.
>> > Is this the right approach? If not, how should I behave?
>>
>> Has Neroth given up development on his version forever? If so, it
>> sounds sensible to me to switch in RPM Fusion.
>>
>> - Ken
>>
>