argument, has been extended to accept all the new forms.
*** Incompatible change in the third argument of 'format-time-string'.
-Previously, any non-nil argument was interpreted as a UTC time zone.
-This is no longer true; packages that want UTC time zone should pass t
+Previously, any non-nil argument was interpeted as specifying Universal Time.
+This is no longer true; packages that want Universal Time should pass t
as the third argument.
*** Time-related functions now consistently accept numbers