WhatsApp has been promising to introduce call functionality for almost a year now, but new images from an experimental build of the app suggest the feature could be close to completion. The "screenshots" above have been created by AndroidWorld.nl’s Sander Tuit, who extracted layout files, images, and text from the raw code of the app hosted on WhatsApp’s website. (This version is more frequently updated than those found in official app stores and often contains experimental features). Tuit told The Verge: "All screens except for the incoming call screen [would] look 99.9 percent like in my constructed screenshots if they released WhatsApp Call today."
Whatsapp promised voice calls some time this year
The images suggest a pretty straightforward implementation of voice calling, with a slide-to-answer function, options to reply by message (including pre-defined texts), and a button to connect Bluetooth headsets. It also seems that users will have the option to record calls and play them back later looking at this code:
Of course, this information is far from confirmed: even though the code for these functions exists, there's no guarantee they'll be included in the final release. However, WhatsApp did say it would be introducing voice calls some time this year — they'll have to hurry up if they want to beat the clock.