Yesterday I released a first tarball of glibmm 2.5, with a first version of the Glib::Option command-line parsing API, wrapping GOption. And last week I released gtkmm 2.5.0, with quite a lot of new API from GTK 2.5, such as IconView. Just so you know.
I've had so little time for gtkmm coding these days, so I really could use some help. For instance, gtkmm needs examples, to test the new widgets. The train journey from Berlin to Munich, almost every week, is 6.5 hours, plus 6.5 hours back, and that's almost the only time that I get to do this stuff.
One of the side-effects of signing up to a time-based release schedule is that you promise to do something by a certain date, though it's only really bindings that promise to implement anything specific. And it's the maintainer that makes that promise, not the other contributors, so the maintainer is the one who actually feels the pressure. But, still, there should be enough time.