I have not been able to find the answer to this anywhere so I am hoping someone here can help.

Lync Phone Edition Devices, more specifically, Polycom CX series checked for updates in the following ways

When a User Signs In

When the Phone Reboots

Every 24 hours by default

https://technet.microsoft.com/en-us/library/gg398740(v=ocs.14).aspx confirms this behavior however it doesn't say what time?

Is it at a specific time every 24 hours or does it randomly perform an update check once every 24 hours?

I think its pretty random. Once it finds an update it will reboot and install when the phone has been inactive for around 5 mins. Thats my understanding.

Hi,

Agree with Andrew Morpeth.

The Polycom Phone will check if there is a newer firmware need to update randomly. When it find there is a new firmware, after a few additional minutes of idle time the phone will automatically reboot, activating the newly downloaded firmware version.

Best Regards,
Eason Huang