Audio and Video Messaging, and more new features like camera effects are coming to Google Duo soon, thanks to bits of code found in the APK of the latest version of the app, which should be version 21 that has started to make the rounds to users. While it had already been detailed in a recent past version of Duo that audio and video messages were coming to the application, this latest version reveals that there will be notifications that users will receive that will alert them to what kind of message has come in from one of their contacts, who the message is from, and give users the option to listen or watch the message via a button accompanying the notification. This doesn't indicate when the feature will show up, but it might not be too far off.
In addition to more details about the audio messages and video messages that are going to be introduced to Duo at some point in the future, Google is also going to be adding in buttons for stopping and starting recordings within the app. These are just new icons to show the availability of this feature, which may not be terribly exciting to most users, but they should still be useful as the buttons look like they'll appear pretty large which could make them easier to spot/notice and easier to use.
Alongside these two new changes that are coming, it looks like there may be options to save messages on the way. Here, it seems like users may be able to save videos from recorded video messages, or it could be that Google is looking to add an ability to save the video as a draft in case the user isn't able to complete the message in one sitting before sending it off. Camera effects are also on the way and Duo version 21 adds a bit more detail on this, hinting that brightness, contrast, and saturation, will be things that users can adjust. It also looks like Google is setting up recorded video messages for having an date of expiration if they aren't watched within a certain amount of time. There's no telling when Google might push these features out, so it's something you'll want to keep an eye out for if you're interested in using them.