Microsoft's offer to upgrade Windows 7 or Windows 8 to Windows 10 for free ended on July 29, 2016. But Microsoft continues to offer some ways to update it completely open.
The free update to Windows 10 is still possible in 2018
On the Windows accessibility page, the company indicates that customers interested in Microsoft support technologies can continue to upgrade to Windows 10 for free.
Although this free update offer ended on December 31, 2017. It is still active today and allows you to download the Windows 10 update executable.
Windows ten update page for accessibility users
During the update process, it is not checked at any time if the user makes use of any assistive technology, nor are these options activated in the installed version of Windows 10. For all purposes, it is a standard update to Windows ten.
Some users have indicated that when they run the update file Windows10UpgraderApp.exe. Also, they get an error because the file API-ms-win-core-library loader-l1-1-1.dll is missing. That is a known problem of Windows 7 that affects other programs besides this installer. But that can easily solve by copying a file from one folder to another.
The update for assistive technologies intends for those who will use the accessibility features of Windows 10. But, as discussed above, there is no verification process involved. So theoretically anyone can update using this method (although you should not if you're not going to make use of those technologies).
Another way to upgrade to Windows ten for free is to use an existing Windows 7 / 8.1 product key to activate the installation of the new operating system, and this mechanism also seems to work in 2018.
Ultimately, it seems that Microsoft is not worrying too much about closing. As free upgrade paths as the increase in the number of Windows 10 users benefit the company.