Update - Added official notes from the patch files.
Patch 4.2.2 now available on Test Realms
Patch 4.2.2 is confirmed'ish and now available for download to anyone who tries to connect on test realms. No signs of community managers today yet, we will most likely have to wait before we get any information on testing and/or patch notes. The PTR servers aren't online yet.
World of Warcraft Patch 4.2.2 - Patch Notes
Originally Posted by Blizzard Entertainment