This from ITS:

On Wednesday 17/05/2017 at 1:00 pm, critical and security updates for Windows 7 and Windows 10 will be released to all Windows PCs and Servers.

Users will be prompted to install these updates by a popup balloon in their system tray. Please install these updates as soon as possible. A restart will be enforced during the update process.

If users have not already installed the updates by Wednesday 24th May 2017 at 11:00 pm, the installation of these updates will be enforced. If a computer is off, or in sleep mode, at this time the updates will be installed the next time the computer is powered on.