This message will be sent to all Wikipedias except frwiki, eswiki, itwiki, plwiki, fawiki, jawiki and ruwiki on approximately Monday, July 10th. (These seven wikis have been notified separately and will see this change before then.) Later, the same message will also be sent to the non-Wikipedia wikis (with a different date in the penultimate sentence).
Thank you. Also, if any of you have concerns about how this may affect any scripts or gadgets that you use, then please feel free to follow the testing directions at the mw.org