The Windows 10 upgrade is automatically blocked (that is, no further action is required) on computers or other devices in the following scenarios:
- The computer or device is joined to a domain.
- The computer is managed through MDM.
- The computer is running any of the following systems that are excluded from this reservation offer:
- Windows 8.1 Enterprise or Windows 8 Enterprise
- Windows RT 8.1 or Windows RT
- Windows Embedded 8.1 Pro
- Windows Embedded 8 Standard
- Windows Embedded 8.1 Industry or Windows Embedded 8 Industry
- Windows 7 Enterprise
- Windows 7 for Embedded Systems
- Windows Embedded Standard 7
- Windows Embedded POSReady 7
for other scenario’s where you need to block the notification check this KB3080351
