Since many of you will likely see it before I do, I'm putting in a placeholder entry to allow discussion. Whoever finds the letter first please leave the link to it.
EDIT: Given the feel of the Sept letters, its possible that there wont be any monthly retcons at all anymore. Post here if anyone finds any official confirm or deny one way or the other. To be safe, I'll leave this entry here so if a letter turns up there's a place to go snark it.