+* The rc_type field in the recentchanges table has been superseded by a new
+ rc_source field. The rc_source field is a string representation of the
+ change type where rc_type was a numeric constant. This field is not yet
+ queried but will be in a future point release of 1.22.
+** Utilize update.php to create and populate this new field. On larger wiki's
+ which do not wish to update recentchanges table in one large update please
+ review the sql and comments in maintenance/archives/patch-rc_source.sql.
+** The rc_type field of recentchanges will be deprecated in a future point
+ release.