For me it is working below 16.04 if I tweak my system.
1. The udev rules tweak isn't needed any more - it is in the package version of the file now correct.
2. Check 'lsmod |grep cdc' - below xenial the modules aren't loaded any more Add to /etc/modules a line with the content: cdc-wdm
After that the gsm modem is working again.
For me it is working below 16.04 if I tweak my system.
1. The udev rules tweak isn't needed any more - it is in the package version of the file now correct.
2. Check 'lsmod |grep cdc' - below xenial the modules aren't loaded any more
Add to /etc/modules a line with the content:
cdc-wdm
After that the gsm modem is working again.