All though the free upgrade offer to users of Windows 7 and Windows 8 has ended, you can still perform free upgrade of your Windows installation via below mentioned trick.
Microsoft is still allowing the free upgrade of Windows 7/8 to Windows 10 for users who are using assistive technologies. Microsoft does not seems to be verifying if the user is actually using any assistive technology during the Windows upgrade process.
How to upgrade?
Visit Microsoft website for users of assistive technologies & download Windows 10 upgrade assistant.
Tags: Windows 10 free upgrade from Windows 7 and Windows 8 via assistive technologies.