The Secret World Issue 3: The Cat God is set to be deployed today, Wednesday, September 26th. The server is expected to come down at 7:00 a.m. Easter Daylight Time (4:00 a.m. PDT) with the downtime expected to last up to three hours.
The name of issue three was released with the announcement last week that Joel Bylos had taken over as the Game Director for The Secret World. Little else is known about The Cat God.
UPDATE: The official update notes and a description of the contents of The Cat God have arrived on The Secret World's site.
Read the announcement on The Secret World's forum.