Good evening,
I am developer with 7 years of experience in telecommunications, especially VoIP (PBX, IP Phones and Softphones). I work directly with Linphone for Android and iOS for about 5 years, and during this time I'm able to make several customizations in Linphone to adapt it features to PBXs(SIP servers). Also I did several modifications in the application interface, fix bug and make improvements. I already published Linphone modification in Google Play store (changing the package name) and Play Store (iTunes Connect) and also able to make modifications in the "belle-sip" and "liblinphone" libraries.
If you have any questions, please let me know.
Thank you for your attention!
Best Regards!
Roberto Filho