Microsoft has recently warned that the OneDrive Desktop app will stop synchronising with all personal Windows 7, Windows 8, and Windows 8.1 computers, starting March 1st, 2022. Before that, the software itself will stop receiving updates starting January 1st.
Business version of OneDrive have a little longer time, as they will have up to January 10th, 2023 (which is the official end date of extended support for Windows 7 and Windows 8.1).
You will however be able to manually transfer files using the web version, e.g., onedrive.com, though that does become a large inconvenience if you use the cloud files often from an older PC.
The reasoning behind all of this is, in Microsoft’s own words, to help “focus resources’ on their newer Windows versions and technologies. Which in layperson terms, Microsoft really wants you to upgrade to at least Windows 10, or one above to Windows 11.
While this is all very sudden for some users, it is not too unexpected as Microsoft has been pushing extremely hard for people to move away from Windows 7 and Windows 8. This change is very much in line with that push, as many may finally upgrade even if they do enjoy their older Windows versions.
You can read more on Microsoft’s decisions here: https://techcommunity.microsoft.com/t5/microsoft-onedrive-blog/end-of-support-for-onedrive-desktop-application-on-windows-7-8/ba-p/2929066