Acrobits has updated its Softphone application for the iPhone and iPod touch adding support for secure calls and improvements to Google Voice integration and call interruption. Acrobits Softphone 4.6 now supports encrypted secure calls using SRTP/SDES and ZRTP; users can receive incoming ZRTP calls at no additional charge but must purchase an add-on feature via in-app purchase to initiate outgoing ZRTP calls. The update also improves the Google Voice integration within the app providing an easier and more intuitive setup procedure and adds a call quality indicator to allow users to view network connection quality in realtime. Users can also now record a message to be played to a SIP/VoIP caller when the call is interrupted by a standard incoming cellular call on the iPhone. Acrobits Softphone is available from the App Store for $7; additional features are available via in-app purchase including G.729 Annex A audio codec support ($10) and encrypted ZRTP outgoing call support ($25).