Cirrus modem LTE not stable in 4.3.7 (AP1300) - Quectel

I saw some threads about the same issue, but none are resolutive.
I have EP06ELAR03A08M4G modem (Quectel) pre-installed in the AP1300.
After updating to 4.3.7 the connection sometimes drops for hours and then comes back.
This is annoying, since I control this modem remotely from a different city. The modem only has LTE connection (no backup) and it is used to provide internet access to IoT devices and IP cams for survelliance.
I tried set QCM, QMI, different APN settings but the issue is still the same.
Any chance to stabilize it ? It’s a problem for me to get it back to 3.x for now…since I live 500 miles away from that city.

Any hint is appreciated.

Thanks a lot for your help,

I forgot to mention that with the same configuration and same sim/operator using 3.217 the modem connection works perfectly without any disconnection.

You have installed the snapshot version 01.01.2024 or the beta? Maybe wait for next snapshots, perhaps will be better. Just in case to save a long trip which for sure will solve your issue.

After reverting to the issue did not solve. I don’t know why.
Then I tried using different USIMs but still the modem hangs for hours during the day.
Could there be some file that it’s not reflashed during downgrade? Is there something in the modem I can try, to get more information when the issue occurs? I saw that the modem has still an assigned IP address when navigation is not working. The traffic is reset istantaneously, not timed out.
As a workaround can someone help me writing a crontab job that runs every x minutes and if it cannot ping a site it will do a “modem reset” (the operation done by the button in the UI, whatever it does, it works for me to get everything working back.

Thanks a lot for your help in advice,