My son has an old laptop with Windows 10 Pro on it. Think originally it came with Windows 7 and we put 8.0 Pro on it when they were selling licences for $50 (so it didn't come for that particular device), and then on up to 8.1 Pro and to 10 Pro.

He's just got a new laptop with Win 10 Home on it. Does anyone know if its possible to apply a key from the old laptop to the new one directly, without having to downgrade to 8.0 Pro (using the licence we bought) and working back up to 10 Pro again ?