Update, April 10: Following the rollout start on March 27, Justin Uberti, tech lead for the Duo project, confirmed on Twitter that audio calling in Google Duo is now available to all users worldwide (via Android Police).

Original post, March 28: And the app updates keep on coming. Following the UI tweaks of the IMDb app and Google Translate’s inclusion of word definitions arrives another considerable app upgrade, this time to Google Duo.

Google Duo version 9, which is currently hitting the Play Store, now features an audio-only call feature. Previously, Duo’s call functionality was restricted to video, but Amit Fulay, the Google Duo and Allo head of product, announced yesterday that audio calling was being activated.

It’s not available in all regions just yet — the functionality hasn’t yet appeared in my app— but 9to5Google notes that audio call-related terms can be found in Duo version 9’s strings, so the core structure is obviously there.

This is a welcome addition to Google Duo as it makes greater attempts to compete with the likes of FaceTime, Skype and WhatsApp. It’s by far the youngest product, and has already received a number of improvements since it was launched last August, but Google is going to need to keep its foot on the gas with regard to these updates if it wants Duo to become a household name.

What are your current thoughts on Google’s video and audio calling app? Let us know in the comments.