I'm using FMC130 with SL320 modem with this firmware without problems https://wiki.teltonika-gps.com/view/Special:Redirect/file/FMB.Ver.03.29.00.Rev.18_and_configurator.zip
and another with this version Ver:03.29.00_13 no problems
Are you using TCP or UDP protocol?
TCP
Ahh, ok i use UDP with AVL response. Will try TCP but 1nce sim card recommends using UDP for some reason.
Having some stability issue on the FMC130 with 03.27.07.Rev.252 . But anything newer just stops working with traccar. Teltonika support was not very useful.
I did some debugging looks like traccar is getting the data points and responds with correct AVL package. But Wireshark shows that UDP message from server to FMC130 gets refused every time (Protocol:ICPM Message:Port Unreachable) .
including a screen shot of 2 devices one with older firmware one with newer .
Any help to figure out what is going on is appreciated.