The homepage, forum, wiki and IRC will be going offline for up to two hours on 2018-05-11, between 12:00 and 14:00 UTC.
For convenience, this means:
EDT (USA east coast):
2018-05-11, 08:00-10:00
BST (UK):
2018-05-11, 13:00-15:00
CEST (Most of Europe):
2018-05-11, 14:00-16:00
AEST (Australia east coast):
2018-05-11, 22:00-24:00
This is a security patch window initiated by the hosting provider. Sorry for the late notice, they let me know ages ago and I forgot to post it here until now.