I upgraded my Google Pixelbook to Chrome OS 81 on April 19, 2020.
I've noticed that the shelf now has new way to display additional items. Rather than three dots I now see a down arrow, which I click to display more icons. An up arrow then displays to scroll back.
Another major feature in Chrome OS 81 is the ability 
to create new Crostini containers that use Debian Buster rather than Stretch. You cannot upgrade existing containers, but if you disable and re-enable Linux apps, the new container will be based on Buster.