Microsoft, Apple, Google, Mozilla and even Adobe itself have all obsolete Adobe Flash technology, which reached the end of its life on January 1
The current update does not remove third-party installations of the Flash Player – only versions bundled with Windows itself. The change seems unlikely to affect most significantly – Microsoft Edge, Google Chrome, Mozilla Firefox and Apple Safari each completed their Flash support before January 1, 2021.
Although Internet Explorer 11 (and the IE mode in Microsoft Edge) supports direct installation of downloaded Flash players as a plug-in, Adobe Flash Player itself has a built-in “kill switch” that causes it to refuse to play Flash content if the system date is later than January 12, 2021.
In addition to all builds of Windows 10, KB4577586 is available and installed as a security update on Windows 8.1, Windows Server 2012, and Windows Embedded 8 Standard.
If you’re worried about the possibility that Flash is still on your system and do not want to wait for the update to become mandatory, you can also download and deploy KB4577586 directly from the Windows directory – and when you’m done, you should be able to safe to play an emulated Flash game hosted in the always wonderful internet archive.