: Acquire the authentic ISO from your Microsoft Volume Licensing Service Center (VLSC).
: Use Rufus or Ventoy to flash the ISO onto a USB drive (8GB minimum). enuswindows10enterpriseltsc2021x64dvdd289cf96iso
: Enter your corporate KMS or MAK volume license key. : Acquire the authentic ISO from your Microsoft
LTSC 2021 does support in-place upgrade from Windows 7/8.1 or from non-Enterprise editions of Windows 10. You must perform a clean install. enuswindows10enterpriseltsc2021x64dvdd289cf96iso
If you are upgrading from en-us_windows_10_enterprise_ltsc_2019_x64_dvd_74865955.iso , you will benefit from:
C90A1DF5D72605AA3D261DA2F18A3701E7E36979A7EE7BEB12FA909E8398DA7D A026C1123D88D16CA8B32ADDC0A7AA669469D50F Architecture 64-bit (x64) Base Build Windows 10 Version 21H2 (Build 19044.1288)