That's something to be added to the documentation:
Locate the folder where the software is installed (C:\Program Files
\DPSD\AisServiceSetup).
Open the file named aisclient.exe.config with a text editor (notepad
or wordpad).
Locate the setting “udpport1” and set its value to 5853 (instead of
the default 5323) which was assigned to you when registering your
station .
Save and close the file. Restart the service AISlogger.
Dimitris