Support for various versions of Windows 10 is ending today, as Microsoft promised in its most recent update in February. Most notably, consumers on the Windows 10 Anniversary Update, or version 1607, will no longer receive new cumulative updates.
Windows 10 version 1607 was released in August 2016, so it's received a full 20 months of support. If you're a consumer that's still on the Anniversary Update, it's recommended that you move to a newer version of the OS.
This change does not affect those that are still using Windows 10 Enterprise or Windows 10 Education. Those customers will continue to receive updates until October 9. Interestingly, Windows 10 Mobile users also have until October, although there's no upgrade path for them.
Windows 10 version 1511, which is two years and five months old, had support ended on October 10 last year, but today marks the end for those on Windows 10 Enterprise and Education. Windows 10 Mobile version 1511 support ended back in January.
According to the latest AdDuplex report, only 3.6% of Windows 10 PCs are still on version 1607, and 0.8% are still on version 1511. In other words, this change doesn't affect a large portion of users. Still, it's nothing new, as these end of support dates have been public for some time.