The maintenance ends July 6, 2021, 15:00 UTC. See the main page for a timer.
The updated server will be opened for everyone. Your old account credentials will work just fine and you'll see your old characters as they were. Only the world has changed a little bit 
A few guides may follow soon.
The previous patcher has an update prompt on launch now. In case you need to download a full client, see here: https://pwmirage.com/download/
