Version 1511 revolutionized the activation process by allowing users to activate Windows 10 directly using valid Windows 7, 8, or 8.1 product keys.
If your goal is a lightweight, stable, and secure Windows 10, consider these much better alternatives: Windows 10 Version 1511 Build 10586 Iso Download
If you download from a third party, compare the file’s SHA-1 hash against official values: and secure Windows 10