Windows 10 Build 14371 has leaked on MDL Forums. But, this isn't an official release and we don't recommend installing it on your primary machine. It comes from the ‘rs1_release_prs' development branch which does not usually push builds for Insiders.
If you still want to try out Windows 10 for Surface Hub, you can install build 14371 on a virtual machine, but only after converting the downloaded ESD file format into ISO format.
It is the Anniversary Update for the Surface Hub and is expected to roll out in coming months. We still don't know if Microsoft is planning to release the same as Windows 10 Anniversary Update for PCs, but we should see an official announcement in coming weeks.
Windows 10 For Surface Hub ships with an altered SKU designed for the big screen, with productivity in mind and hooks on Azure and business domains.
It offers quick access to Skype video calls, a OneNote whiteboard for drawing and annotation, and a shortcut for connecting to another nearby Windows 10 device. Signature Windows features still remain but with a lot more on offer.