This app can download, store and install APN configuration profile (*.mobileconfig file).
When you change the SIM card, in some case, you need to install APN configuration profile to connect to the mobile network.
Usually, the APN configuration profile is provided on a web page of the mobile network operator. But since you already have changed the SIM card, you already have lost the network connection at that time. So, you need a Wi-Fi connection to download it. If you can not find Wi-Fi connection at that time, you can not download it...
This application helps to install APN configuration profile without Wi-Fi connection.