Hi,
We are be testing our secondary data centre. This will make sure that the wikis can stay online even after a disaster. On October 10, from a bit after 14:00 UTC and for up to an hour (but probably not that long), you won't be able to edit the wikis. This has been repeatedly mentioned in Tech News, posted on Village Pumps etc, but please help spread this in your communities, especially with regards to editathons etc.
You'll find more information here: https://meta.wikimedia.org/wiki/Tech/Server_switch_2018
//Johan Jönsson --