The folks at Mailbox have had a pretty good week. Not only were they acquired by Dropbox—to the tune of what some are reporting to be $100 million in cash and stock—last Friday, but they just filled their 1 millionth reservation.

To celebrate, the team has released the first update for the popular email client since it was released to the public back in February. The update brings the app to version 1.1, and includes a new ‘shake to undo’ feature, and more…

Here’s your full 1.1 change log:

What’s New in Version 1.1.0

-Shake to undo!
-UI enhancements
-Bug fixes and performance optimizations

Though I haven’t spotted the UI enhancements yet, I will say that the new Shake to undo feature is nice. With Mailbox’s swipe gestures, I get going through my inbox pretty fast. And it’s nice to have a quick way to undo my mistakes.

As far as the milestone goes, garnering and supporting one million users in just 6 weeks is impressive for anyone—especially for something as tough as email management. But sadly, a reported 400,000+ people are still waiting in line.

The team says that fulfillment times have improved though, and should continue to do so now that Mailbox has backing from resident cloud expert Dropbox. If you haven’t signed up yet, you can download the app for free from the App Store.