While Windows 10 Pro, Home and Mobile are the main versions of the Microsoft's operating system, there are a bunch of other versions for specific markets. Until last week, that number was 11. But an accidental release last week saw that number increased with three new versions.
The new versions, Windows 10 Pro for Advanced PCs, Windows 10 Pro N for Advanced PCs and Windows Server 2016 ServerRdsh have been reported at MSPowerUser who gained the information from a poster at the My Digital Life forums.
For most of us, this probably doesn't change things much. Most likely, these are specific SKUs that aren't functionally different from any other Windows 10 release but are targeted at specific licensing agreements.
If you think that might be you, it might be time to call your account rep to see if any new licensing options are coming your way.