Advanced warning from Linden Labs: scheduled maintenance for 9/18 6:00 - 9:00 AM PDT! I think it likely they'll underestimate the amount of time it will take to perform the job and we may experience issues throughout that day. If anyone is planning an event for the 18th, you may want to reconsider another day.
EVERYTHING will be down. If you somehow manage to log in, it is highly advised not to rez objects, make any purchases with or for Lindens, nor make any changes to your account.
For more information, please see the official Second Life blog: https://status.secondlifegrid.net/incidents/y3nf5sqmjnk0