Today, January 12, is the last time Microsoft will deliver security updates to almost all of those still using versions of Internet Explorer older than IE 11.
Those running Windows Vista, Windows Server 2008, Windows Server 2012, certain Windows Embedded variants still have more time. But anyone with Windows 7, Windows Server 2008 R2 and Windows Server 2012 R2 need to be on IE 11 starting tomorrow to continue to get security updates. Here's Microsoft's chart listing which version of IE users need to be running to get continued support after today.
Microsoft began warning users in 2014 about the January 12 IE support cutoff date. But all is not lost for the majority of those who are still running IE 8, 9 or 10 because of legacy dependencies.
There is a way to view intranet sites and internal apps in their companies that were built specifically for an older IE variant. Microsoft built a backward compatibility/emulation "mode" into IE 11 called Enterprise Mode, designed to eliminate the vast majority of these incompatibilities. Enterprise Mode in IE 11 enables users to run many legacy web applications that were designed for older IE versions by emulating IE 7 or IE 8.
Word about IE 11's existence first leaked two years ago. Initially, Microsoft was encouraging Windows 7 users to access this mode so they could move off IE 8, which originally shipped with Windows 7, to a more recent version of IE.
The Microsoft Australia OEM Team blog has a three-part blog post series about IE's expiration of support with a good list of resources that might help those needing to move to IE 11.
A few of those links:
Even if users aren't using IE at all on a Windows or Windows Server 2008 R2 machine, Microsoft is still encouraging them to move to IE 11 because there are browser components inside the Windows operating systems themselves that need to be kept secure.
"In order for IE related Windows components to update, you will need to be on the latest version of IE. If you're planning on removing IE, you should upgrade to the latest version first and then remove IE," according to a recent Microsoft blog post.
A related aside: January 12 also is the day when Microsoft will provide its last security updates to those still running plain-old Windows 8 (not Windows 8.1) on PCs and tablets.