Chrome OS 84 was released to the stable channel on July 21, 2020. page 
Key new features: * Create split screen views directly from overview mode * Can drag and drop apps between monitors when display is in extended mode * [Files app UI](https://chromeunboxed.com/chrome-os-84-update-feature-files-app-material-design/) is refreshed * Linux apps can now access the microphone * Take pictures using the volume buttons when in tablet mode * Re-size the virtual keyboard
Looks like a feature from the beta version didn't make it to stable, which is to drag and drop Chrome tabs for split screen mode while in tablet mode. reddit
I've installed Version 84 on my Lenovo Duet and Google Pixelbook and I have observed the features described above.