Merging two apps was always going to be a complicated process. Add to that the overall confusion around Google's messaging strategy and you can imagine what this looks like, but what Google is basically doing here is bringing all of Meet's capabilities to the Duo app and then turning that into the new and updated Google Meet app.
In July, Google already started adding more of Meet's capabilities to Duo in preparation for the transition, while Meet also got an update and a new green icon. Oh, and the Google Meet app is now called "Google Meet (original)." Users who don't follow along with every turn and twist of this saga will surely wonder about that for a few seconds, before dropping into their next unnecessary meeting and forgetting all about it.
Starting today, Google will release an update to the Duo app for Android and iOS that will feature the new Meet logo, as well as a new notification in the app that explains what's happening.
Because the Duo app already features Meet's meeting capabilities today, there aren't any major functional updates here, but it's worth highlighting that you'll need a Google account to use these meeting features (before, to use Duo, all you needed was a phone number).
Come September, all users will see the new Google Meet icon and app name. At that point, if you want to install Meet from Google's Play Store or Apple's App Store, you'll get the updated Google Meet app (which used to be Google Duo) with the combined video calling and meeting features.
If you're currently using the Google Meet (original) app, you can continue to do so for now, you just won't get the new ad hoc calling features. At some point, though, that app will go away. "We’ll inform you when you should migrate to the new app experience," Google says.