I was using the Airtel 4G LTE modem (Huawei E398) with the Airtel connection manager successfully in Ubuntu 12.10 (in one partition, have Ubuntu 13.04 in another partition). Upgraded to Ubuntu 13.10 2 days back and since then I couldn't get connected. The Airtel connection manager would start but not detect the modem. I tried adding a connection manually but that did not work either. Any insight would be helpful.
After looking at various daunting options, I realised that the connection manager's configuration could have been replaced during the upgrade. So, I uninstalled the connection manager (uninstallation steps from here)
cd /usr/local/airtel sudo ./UninstallMobilePartner
As soon as I uninstalled the Airtel connection manager, the modem was detected in the Ubuntu network-manager and I was able to create the connection manually, which is working now. Also, I want to inform that 13.10 has an exhaustive list of Indian operators and modems in the network manager.