Microsoft provides information to Paul Thurrott blocker windows to stop production lines. Surface 3 last year 2016. And now the products in stock are limited (in the web Microsoft Store now only one sub version is 64GB / RAM 2GB / Wi -Fi + LTE from all 4 digestible version).
The opening Surface 4 will happen when not identified and Thurrott also agree that does not know inside information at all.