I have to admit this has been my biggest concern with a lot of the extensions out there. Lack of support when new a core upgrade hits so if you want the new functionality, it may break your extensions so you have to choose to give up one or the other (usually a major point release however).
Not a fault to the core developers, but just a concerned user and one reason I haven't moved down the extension path much (which would help extend functionality a great deal).
You'd expect some delay with any new release, but Abantecart 1.1.9 came out in May 13th, 2014 so year+ is pretty slow IMO.
My assumption is most/all developers don't have enough buyers of the extension to make it worth their while (and they have a regular full time job as well) making updates hard to do super quick. I'm sure they do good work and give good support, just random thoughts from a user.
