It’s official, Microsoft has acquired Sunrise, the maker of one of the best calendar apps for iOS and Android. Rumors suggested Microsoft was willing to pay $100 million for the purchase, but neither side is yet disclosing financial terms of the deal. Microsoft first made the news official with a new video posted to its YouTube page, later releasing a statement. Sunrise's co-founders say the Microsoft pact is "just the beginning" of a promising future and are emphasizing that the current app will remain available on its current platforms. "We're not going anywhere," the company said.

The move comes less than two months after Microsoft acquired Acompli, a mail app for iOS and Android, and days after the software maker rebranded that app as Outlook. Microsoft’s Outlook app is now one of the best email apps on Apple’s iOS platform. “Today’s acquisition of Sunrise, our recent acquisition of Acompli and our new touch-optimized universal Office apps for Windows 10 all exemplify Microsoft’s ambition to rethink the productivity category," said Rajesh Jha, corporate VP of Outlook and Office 365.

Sunrise supports a number of features you’d want to organize events, including recurring appointments, alerts, birthdays, Google Maps directions, and more. Sunrise currently supports Gmail accounts and Facebook events / birthdays from the social network. The iOS and Android calendar app also integrates well with popular services like SongKick and TripIt to map upcoming gigs and help plan trips. There’s even Foursquare integration to see a history of places you’ve visited, and Evernote features to let you view reminders inside Sunrise. So Microsoft's interest in Sunrise is understandable, it's simply the Swiss Army knife of calendar apps.

It’s not clear how Microsoft plans to use Sunrise in future, but it’s reasonable to expect the company will fold the features into its Outlook app. Outlook on iOS and Android has its own calendar, but Sunrise’s features are a lot more powerful so it would make a lot of sense to combine the two. The acquisition is yet another step in Microsoft's plan to own productivity across multiple platforms, and expand its mobile Office suite.