What’s new in ADFS 2016?

https://technet.microsoft.com/en-us/windows-server-docs/identity/ad-fs/overview/whats-new-active-directory-federation-services-windows-server-2016?f=255&MSPPError=-2147217396

You can upgrade an AD FS 2012 R2 farm using the “mixed farm” process described here. It works for WID or SQL farms, though the document shows only the WID scenario.