Gave the new datetime.strptime() a versionadded blurb.

Doc/lib/libdatetime.tex

@@ -631,6 +631,8 @@ Other constructors, all class methods:
   format)[0:6]))}. \exception{ValueError} is raised if the date_string and
   format can't be parsed by \function{time.strptime()} or if it returns a
   value which isn't a time tuple.
+
+  \versionadded{2.5}
 \end{methoddesc}
 
 Class attributes: