What/when was Garry's Mod 12?

I know gmod “10” was released in 2006, and gmod “11” was released with the orange box update in 2008, and there is an upcoming gmod “13” update this September, but what was gmod “12”? Was it the toybox update?
(Sorry I couldn’t find any fitting subforums)

When GMod moved from the orangebox engine to the latest TF2 engine afaik