what is the difference between Zoiper free and premium for iOS?
Hello,
Zoiper Premium SIP Softphone supports some additional features that are not available in the free version. The features are Call-transfer, 3-party conference, Call recordings, ZRTP encryption, Presence and Wideband codecs (G.722, G.726, Opus, etc.). You may review and download Zoiper Premium SIP Softphone from here:
https://itunes.apple.com/us/app/zoiper-premium-sip-softphone/id787863350?mt=8