On Saturday July 22, all power, including emergency power, in the Huygens building will be switched off for planned maintenance from 08:00 until 12:30. If all goes well, power will be available from 12:30. We expect to need at least a few hours to get all Science services up again. During this time, all but a few basic services will be unavailable. Most servers will be turned off the Friday before. We will attempt to maintain basic DNS/DHCP, SMTP(mail) and license services, but for instance the science mailboxes, home directories, websites, VPN, fileservers, Gitlab, loginservers and compute clusters will not be available during the off period.