You are downloading the Sipmobile XAP file v18.104.22.168 for Windows Phone. Sipmobile is a free and useful Social app: Free calls to US and Canadian numbers. Free calls to more than 2000 VoIP networks. For instructions please visit ... You can now download the offline XAP file to install & try it.
Download Locations for Sipmobile 22.214.171.124 XAP file
Note: To install it manually from an SD card, you should choose one of the server location above to get the offline Sipmobile XAP file, move the file to your phone's SD card and then tap 'Install local apps' in the phone's App list.