When Microsoft released the Windows 8.1 Update, IT feathers were ruffled by Microsoft's decision to make it a compulsory update: without it, Windows 8.1 systems would no longer receive security fixes. As spotted by Computerworld's Gregg Keizer, Microsoft is applying the same rules, at least in part, to Windows 7.
Windows 7 users who've installed Internet Explorer 11 are required to install the KB2929437 update. This is the Internet Explorer 11 update that corresponds to the Windows 8.1 Update; it doesn't just include security fixes for Microsoft's browser. There are also some new and improved features, including a more capable WebGL implementation and some additional high performance JavaScript features. If users don't install the update, Windows Update will not provide any more security fixes for their browser.
For the next couple of months, Microsoft is actually still making security fixes for the original Internet Explorer 11 on Windows 7 release, but anyone who wants to use them will have to either download and install them manually, or install them through Windows Server Update Services (WSUS), Windows Intune, or System Center Configuration Manager. Even this avenue will end in August. This will give conservative corporations only a limited amount of time to actually test and validate the updated Internet Explorer 11.