Did m$ released patch for unsupported windozes after Wannacry hit?

Wannacry hit on 2017-05-12 using exploit generously donated by the NSA. For supported windozes the bug was fixed in 2017-03 for unknown reasons. Looks like for unsupported windozes like XP the patch was released on 2017-05-13 after Wannacry hit: http://www.catalog.update.microsoft.com/Search.aspx?q=KB4012598 Is it really so?