Today, the answer is definitive: If you had already upgraded during the free period or used the key to activate Windows 10 before September 2023, your digital license remains valid. But for a new build or a clean install on a machine that never ran the upgraded version, the Windows 7 key will be rejected.
Even after the official free upgrade period ended in July 2016, the activation servers were never fully locked down. For years, users discovered that a clean installation of Windows 10 would still accept a valid Windows 7 key during setup. Microsoft, perhaps recognizing the value of keeping users within its ecosystem rather than losing them to competitors like Chrome OS or a pirated copy of macOS, quietly allowed this "loophole" to persist. can i activate windows 10 with windows 7 key
However, technology is never static. In late September 2023, Microsoft officially closed this chapter. The company updated its activation servers to no longer accept Windows 7 and 8.1 keys for new Windows 10 installations. This change was announced in an updated support document, marking a definitive end to the free upgrade path nearly eight years after its official conclusion. Today, the answer is definitive: If you had