2.51.7 (unstable):

Glib:
* SettingsSchemaKey: Add missing value/range methods.
  (Daniel Boles) Bug #774903
* Variant: Replace throw(std::bad_cast) with noexcept(false),
  to fix the build with C++17.
  See https://bugzilla.redhat.com/show_bug.cgi?id=1438766
  (Murray Cumming)
* VariantType: Deprecate first() and next(). Add get_item_types()
  (Kjell Ahlstedt) Bug #775741

Gio:
* ActionMap: Add add_action_with_parameter() that takes a parameter type,
  and deprecated the existing method, because it cannot work.
  (Daniel Boles) Bug #774444
* SimpleAction: Make set_state() public.
  (Daniel Boles) Bug #777953

Build:
* MacOS: Correct build without gdesktopinfo.
  (John Ralls) Bug #781947
* Glib::Object: Suppress deprecation warning for g_object_newv() with glib 2.54.
  (Kjell Ahlstedt)


2.51.6 (unstable):