Comment 196 for bug 1218322

@William Hua, I have updated packages from proposed repo, so currently i got
  gnome-control-center 1:3.6.3-0ubuntu45 amd64
  gnome-settings-daemon 3.8.5-0ubuntu10 amd64
but still CapsLock switching does not work for me. Microsoft Natural Keyboard 4000, en-us and ru-ru layouts.
CapsLock binding is dispayed as Next Group in Text Entry Settings and as Mod2 + Next Group in Keyboard Shortcuts.

As @Sebastien Bacher said, "next-group issue should be fixed in the ppa version" but proposed version is newer than PPA's, so apt says that there's nothing to update.

P.S.: Also as i mentioned before, switching between layouts, say, with Alt + Shift L or whatsoever, also turns off NumLock.