Hi, I can make your VoIP linphone (voice-over IP softphone, SIP client and service) app work when the phone is locked and work on push proxy server.
Can we discuss this over personal chat if you are available?
I am a professional and among the top 10% freelancer with great communication skills and a great track record.
Please write to me if you have any questions to ask me.
Kind regards
Sachin T.