I'm a huge fan of GLib/Gtk's new macros warning you when using API which is older than a specific version or newer than another version. See for example:
AC_DEFINE(GDK_VERSION_MIN_REQUIRED, GDK_VERSION_3_0, [Ignore post 3.0 deprecations])
AC_DEFINE(GDK_VERSION_MAX_REQUIRED, GDK_VERSION_3_0, [Prevent post 3.0 APIs])
Would be ace to have the same magic in tp-glib!
(That's actually GDK_VERSION_MAX_ALLOWED)
We should probably introduce those macros in 'next' directly as we are about to break the API.
Simon proposed a patch in bug #49400
*** This bug has been marked as a duplicate of bug 49400 ***