Over-the-top provider Line2 (www.line2.com) has officially rolled in the Opus codec into the latest version of its Apple iOS communications app. Line2 is incorporating the IETF certified codec into all of its future apps for 2013 release.
The announcement came in an October 18, 2012 blog post. Line2 version 9.0 for the iPhone, iPad and iPod touch (and presumably all iOS iThings). Line2 says a suite of redesigned applications for Windows, Mac and Android are forthcoming.