S
though it was pretty much expected but HTC just made official that they wont upgrade phones with 512 mb ram to JB
HTC One v and desire c not getting JB
Customs roms 
Its not a good idea to run JB with 512MB ram.
processor of Desire C (and same for Desire V) is really underpowered to use triple buffering required for Project Butter. One will end up with a laggy system instead of buttery smooth.