"Signal on iOS behaves similar to the Android implemen- tation. A simple [zrtpCall] is shown in Figure 11a. Its behaviour only differs for [termError]: While the An- droid client successfully terminates the connection, the iOS client hangs at the screen indicating that the key agreement is still in progress, as shown in Figure 11b." (page 12)
CSipSimple, Jitsi and Linphone Android appear to failed protocol tests (page 9).
"Signal on iOS behaves similar to the Android implemen- tation. A simple [zrtpCall] is shown in Figure 11a. Its behaviour only differs for [termError]: While the An- droid client successfully terminates the connection, the iOS client hangs at the screen indicating that the key agreement is still in progress, as shown in Figure 11b." (page 12)
CSipSimple, Jitsi and Linphone Android appear to failed protocol tests (page 9).