The "official" answer from Microsoft is ; they do not currently offer free upgrades from Windows 8.1 to Windows 10. However, real-world experiences vary:
Microsoft officially blocked using Windows 7 or 8 product keys to activate fresh installs of Windows 10 or 11. can you download windows 10 on windows 8
Some users report that an "in-place upgrade" (running the installer while logged into Windows 8) may still result in an activated system if the original license was genuine. The "official" answer from Microsoft is ; they
If the upgrade does not auto-activate, you will need a valid Windows 10 product key to remove the "Activate Windows" watermark and access personalization settings. Preparation: Before You Download If the upgrade does not auto-activate, you will
Yes, you can download and install Windows 10 on a computer currently running Windows 8. While Microsoft officially ended the free upgrade period in 2016, and tightened activation "loopholes" in September 2023, the actual software remains available for download and installation.