As it has been said, CC has been retired, and scirra themselves recommands not using it, due to his buggyness, need of workarounds to use it properly, lack of support and documentation (even though I think there are somewhere), even though the source code is availiable, they recommand not using as a base nor update it since it was badly done for such a project, that is why C2 has been done from scratch.
However sole people are still using it (I know the french unoficcial forum were mostly around CC when I joined it, mostly due to misjudgement of html5 and "all hail to mighty CC" but maybe you can find elsewhere a place with more people using it.)