Microsoft also tightened up the wording as to what kinds of security updates Windows 7 and Windows 8.1 users will get once that date comes.
"After July 2018, all critical Windows 7 and Windows 8.1 security updates will be addressed for Skylake systems until extended support ends for Windows 7, January 14, 2020 and Windows 8.1 on January 10, 2023," according to today's blog post. (Again, this is only for machines on the list of Microsoft and OEM-supported devices.)
In January, Microsoft execs said they would continue to provide "the most critical Windows 7 and Windows 8.1 security updates" which would "be released if the update does not risk the reliability or compatibility of the Windows 7/8.1 platform on other devices,"
Before Microsoft's mid-January announcement, business users expected to be able to buy new Skylake/Intel sixth generation Core PCs and, if wanted and needed, downgrade them to Windows 7 or 8.1, yet remain supported by Microsoft.
Windows 7 SP1 is currently in extended support, meaning Microsoft had said it would provide users with all security updates on that operating system until January 14, 2020. Windows 8.1's period of extended support isn't set to end until January 10, 2023.
But Microsoft abruptly changed its support guarantee in January. As long as users were running older processors -- those in Intel's Haswell family, for example -- the same support cutoff dates remained for Windows 7 and 8.1. But users who wanted, for various compatibility/test/budgetary reasons, want to run 7 or 8.1 on Skylake or newer processors now faced a much shorter support runway.
Microsoft officials attributed today's changes to customer feedback. But the company is, unsurprisingly, continuing to advocate that users migrate to Windows 10 as soon as possible on all Skylake devices and their successors.