In Summer 2015, Microsoft released their first ever stable Windows 10 OS release to the world! In May 2017, support is ending for this build.
If you were one of those few people who managed to trick Windows 10 into not installing the Anniversary update, now is the time to upgrade. The Creators update will be coming in April 2017 as well, so you may want to upgrade to that as well.
If you Use Windows 10 at work, contact your system administrator with advice, a link to this blog post, or something else to warn them if they are still using Windows 10 without the Anniversary Update.
If you don’t upgrade, your PC will continue to run but won’t be as secure. SeaSurf will still be supported on this version of Windows 10 for a while, though.