Determine AD forest and domain level
Get-ADDomain | select domainMode, DistinguishedName 
Get-ADForest | select forestMode
From <https://www.petri.com/raise-active-directory-domain-and-forest-functional-levels-using-powershell>
Get-ADDomain | select domainMode, DistinguishedName 
Get-ADForest | select forestMode
From <https://www.petri.com/raise-active-directory-domain-and-forest-functional-levels-using-powershell>