When the server starts it validates the license file provided at installation.  If the expiry date set in the file has passed, the server tries to communicate with the central validation service, PCS.

If allowed the server asks the central license validation service if it is allowed to continue. If yes all is good. If no system will log events instructing admins about this.

If failing to communicate with PCS events will be logged and the server will try again within 24 hours.

Once every 24 hours the server will contact PCs service for license validation.  If  license has expired an event will be logged and the server will try again after 24 hours.

After 7 consecutive license expiry events, the server will shut down some of its functions. 

Online verification can be turned off.

In the boot.json add :

"allowonlinelicensecheck": "true" to the top level of the document.

Note that license updates now MUST be done by replacing the license file manually.