Originally Posted by
Squintina
While it's true the letter doesn't say 20th, the reason we're assuming 20th is because it was announced by the team on a stream to be for the 20th (might be 19th in some places though. Japan is ahead of the US and Europe by quite a lot).
Also if you look at the topic on dates that might have maintenance (and thus people shouldn't have weddings on):
- From sometime in between Jan. 19, 2015 7:00 a.m. to Jan. 20, 2015 7:00 a.m. (PST)
- From sometime in between Jan. 20, 2015 7:00 a.m. to Jan. 21, 2015 7:00 a.m. (PST)
- From sometime in between Jan. 21, 2015 7:00 a.m. to Jan. 22, 2015 7:00 a.m. (PST)
So a day for the patch, and 2 days for any emergency quick patches that might come up as people discover issues that were missed.