As of today, Windows Server 2016 is also available in the MSDN subscription:
Windows Server 2016 was or is already available as Eval version available. Die Demo läuft allerdings „nur“ 180 Tage. Jetzt gibt es Windows Server 2016 auch im MSDN mit entsprechenden Produktschlüsseln die nicht zeitlich begrenzt sind.
I've been waiting for this, now it's time to update my own small environment. Exchange 2016 is also supported for Windows Server 2016.
Apparently I'm not the only one who has noticed:
I have an installation guide for Exchange 2016 on Windows Server 2016 already here published.