The last "R2" (Release 2) version was . For Windows Server 2016, Microsoft moved to a different update cadence, releasing semi-annual channel updates (versions 1709, 1803, etc.) alongside the Long-Term Servicing Channel (LTSC) version, which is simply called Windows Server 2016 Standard .
DISM /online /Get-CurrentEdition Get available target editions: windows server 2016 standard r2 download iso 64 bit
DISM /online /Set-Edition:ServerStandard /ProductKey:XXXXX-XXXXX-XXXXX-XXXXX-XXXXX /AcceptEula Note: Replace the X's with your genuine 25-character product key. Add the key permanently: The last "R2" (Release 2) version was
DISM /online /Get-TargetEditions Convert to Standard with your retail key: releasing semi-annual channel updates (versions 1709