Ford web offers me 3.0.20204 - Syn3Updater doesn't list

You will need FORScan and an OBDII adapter.

See this thread:
Updating APIM Firmware (Calibration Files) - Ford / Sync 3 - CyanLabs Official Community

Just read the part at the beginning about FORScan…

Here is another good tutorial:
https://docs.google.com/document/d/1…it?usp=sharing