There have been reports since January that Instagram is working on a new voice and video calling system.
Judging by the fact that these icons can be found on the latest Instagram APK allows us to believe that the team has made some decent progress. We might see this feature available in the not so distant future.
It is not uncommon to see dormant files or features lying dormant in app APKs before they are released. The icons were found lying around dormant in the APK, and it seems as we just have to wait for Facebook to “flip the switch”.
One spokesperson from the company told TechCrunch that they cannot comment anything about it. And when they were asked about it back in January, they did not comment at all. It seems that they are keeping their mouth shut until the service is out for the public.