Hello,
thank you for your question. This is a new feature for FM36XX devices so the manuals are not updated yet. Please see the parameter IDs below:
1255 - Fota Web (0 - Disable, 1 - Enable)
1256 - Fota Web Server (fm.teltonika.lt)
1257 - Fota Web Port (500)
1258 - Fota Web Period (minutes - default value 720)
You can find all the information about SMS commands in the link below. In this case, "setparam" command is to be used, with login and password in front of the command, or two spaces, if there is no login/pass configured. Then space, parameter ID and value. For example - "login pass setparam 1255 1" or " setparam 1255 1" commands will enable the Fota Web feature.
https://wiki.teltonika.lt/view/FM3612_SMS/GPRS_command_list
We hope that helps. Have a nice day.