The official Windows versions jump from Windows 11 (build 22000 and up) to Windows 12 (rumored / early builds as of 2026). There is no Windows 121, Windows 11.1, or Windows 10.121 in any legitimate release channel.
If you see a “Windows 121 ISO” link, treat it like a popup ad telling you that you won a free cruise. Smile, close the tab, and go download the real thing from Microsoft. windows 121 iso file link
To get a clean, official copy, follow these steps on the Microsoft software download page: The official Windows versions jump from Windows 11
: Choose the "multi-edition ISO" for x64-based devices. close the tab