What’s New in Windows 10 Cumulative Update KB4598291 Feb 3, 2021 16:22 GMT New optional cumulative update is now available Microsoft has released a new Windows 10 cumulative update preview for testing, only one week before the company is projected to release a new round of security fixes as part of the February 2021 Patch Tuesday cycle. The new update available today as optional is KB4598291k for Windows 10 version 2004 and Windows 10 version 20H2, and it comes with plenty of fixes, including for a bug that makes it impossible for users to open a document stored on the desktop. At the same time, Microsoft says this update resolves an issue causing a device to stop responding when a game runs in full screen mode, as well as a glitch that suddenly causes some Windows 10 Education devices to be listed as not activated.