I found this information on the Ford Escape forum. I am going to call the dealership where I just bought my 2018 Edge and see if they can confirm and order it in.
From the Escape forum:
The part number is live and the update is on USB from Ford.
Part Number is VJJ5Z19H449A SYNC 3 USB W/ License file NA1.16 1
You must have: Vehicle VIN SYNC ECU Serial Number (ESN) found at the bottom of the General Settings. It is an 8 alphanumeric number. If it looks like it starts with a W, that actually is V V. Must have software version 2.0 or higher installed If not, then Sync 3 will require additional updates before the software can be installed. Must also have Nav 1.14 or 1.15. Those are current versions on 2016-17. Install is estimated at 70 minutes. Price is $150 + tax.