Microsoft has given more detail about a Windows update that will help it identify how many PCs are running old versions of Office 2013, 2010, and 2007. 

The Microsoft work productivity software still works if you bought a license in the past 13 years, but Office 2013, Office 2010, and Office 2007 won't get patches anymore or already don't. Microsoft wants to know how many Windows PCs are still running these old versions from before the days of cloud productivity apps and is doing it via an optional Windows update which launched last month.

"This update is intended to help Microsoft identify the number of users who are running out-of-support (or soon to be out-of-support) versions of Office, including Office 2013, Office 2010, and Office 2007," Microsoft says in a document detailing its update KB502175. 

"Versions of Office that are no longer supported do not receive security updates that provide the latest protections against known vulnerabilities. Also, unsupported versions might face performance and reliability issues over time," it adds. 

Microsoft released the update to Windows 11 22H2 users in the Windows Release Preview Channel (the channel before general availability) in mid-January, as reported by German tech site Deskmodder, but recently re-released it via Windows Update to all Windows users and has updated the information about it here as spotted by The Register.

The update comes ahead of the end of support for Office 2013, which arrives on April 11. After that, there are no more extended security updates. The Office apps still work, but Microsoft won't patch newly discovered or old bugs that could be exploited by attackers to take control of the PC and operating system. 

"All of your Office 2013 apps will continue to function. However, you could expose yourself to serious and potentially harmful security risks," Microsoft warns. 

"Versions of Office that are no longer supported do not receive security updates that provide the latest protections against known vulnerabilities. Also, unsupported versions might face performance and reliability issues over time," it notes in another document. 

"This update gathers diagnostic and performance data to estimate the usage of installed Office versions to determine how best to support and service these systems. This data is gathered from registry entries and APIs. The update does not gather licensing details, customer content, or data about non-Microsoft products," Microsoft said.

Windows users who have Office apps installed are getting an update from Microsoft automatically if they have opted-in to the "Receive updates for other Microsoft products" in Windows. Users can check if they've done that in the past by going to Windows Update > Advanced Options.

Users don't have to restart the computer after installing the update, according to Microsoft.