Microsoft won't support general-purpose Surface devices running the Long Term Servicing Branch (LTSB) of Windows 10.

Credit: Microsoft Microsoft posted this information on its Technet site on October 21. When I asked whether this was a new policy, a company spokesperson said "this info has been communicated with customers from the beginning."
I've seen some say, "makes sense," when that information was tweeted over the past week by various sources. But I have to say this is the first I've heard this. I searched through various TechNet and other Microsoft posts about Windows 10 servicing and could not find a previous mention about this Surface exemption.

Other Windows PC makers haven't imposed similar attempts to limit the ability of users of other Windows 10 devices to make use of LTSB (that I know of, at least).

Microsoft's official reason for the Surface LTSB policy:

"LTSB prevents Surface devices from receiving critical Windows 10 feature updates and certain non-security servicing updates. Therefore, LTSB is not supported as a suitable servicing solution for general-purpose Surface devices. As a general guideline, if a Surface device runs productivity software, such as Microsoft Office, it is a general-purpose device that does not qualify for LTSB and should instead run Current Branch (CB) or Current Branch for Business (CBB)."

Read more: Microsoft says no to Windows 10 Long Term Servicing branch on general-purpose Surfaces | ZDNet