I have bought two EC-25 E modems,
But I have a issue that the modems disconnects from internet after 24 hours of running.
I have tried debugging but found nothing.
How can I check if the modem has the last firmware?
I encounter the issue in OpenWRT and in ubuntu server using QMI.
Most likely this is a provider initiated disconnect and that has no relation to your modem, OS, etc.
You can switch from QMI to ECM and then your modem will take care of the reconnects.
There is a single AT command that could be found in the EC25 AT command guide and/or by a simple google search query. AT+QCFG="usbnet",1
then reset or power toggle