Following rumors and leaks that fueled internet speculation, Microsoft today announced its acquisition of mobile email client Acompli. The Android and iOS app debuted only 18 months ago as a productivity-focused approach to email, and will now be folded into Microsoft’s Outlook team following a reported $200 million purchase. The app will live alongside Microsoft’s growing portfolio of cross-platform mobile applications, and will support the Redmond giant’s efforts to diversify its software offerings and reinvent its core services.

Acompli makes use of swipe gestures for email triage popularized by Mailbox on iOS, and takes advantage of “Getting Things Done” productivity methodology to schedule emails for later and delegate emails as tasks. Significantly, Acompli also includes features to manage calendars and contacts within one app experience, inclusions that drew comparisons to Microsoft Outlook long before rumors of an acquisition began to circulate. What’s more, Acompli’s integration of Google Drive, Dropbox, and Microsoft OneDrive offers seamless attachment sourcing and mirrors features added in iOS 8. The app has seen widespread adoption among productivity-minded users and businesspeople, and provides one of the best Exchange experiences on mobile.

Microsoft is a company in transition, and wide-ranging mobile experiences form a significant part of its ongoing strategy. After bringing Office to Android and iOS—and marking their prices down to free—the company has demonstrated a commitment to cross-platform native apps that go beyond its Windows Phone platform. Rather than developing mobile apps and services that are relegated to Windows Phone, Microsoft has begun investing in products that are available to the wider audience on Android and iOS—including some that don’t support Windows Phone at all. As it streamlines its own software platforms and simplifies processes for developers, Microsoft is simultaneously looking to capitalize on the enormous market opportunity controlled by its platform rivals.

Several massive players in email—including Google with its new Inbox app—are looking to reinvent and transform how the decades-old messaging platform behaves. With Acompli, Microsoft now commands a powerful and feature-rich email entrant on mobile. As it stands, the company offers a barebones “Office Web App” email client on iOS and Android, but Acompli represents a fully realized email experience that supports Microsoft’s Outlook and Exchange products. Over time, Acompli could grow to become Microsoft’s primary email offering on mobile, and encompass many of the features that make the desktop incarnation of Outlook so popular.

One acquisition doesn’t tell the full story, and for a company as influential as Microsoft, there are many more decisions at play. But the company’s recent trend of diversification and breadth signify a new strategy that reflects its mobile platform’s third-place market position. Microsoft and Satya Nadella have a plan to adapt to the new technology landscape, and are making plays that will take advantage of mobile and wearable trends. While the Microsoft of fifteen years ago seemed destined to control the future of personal computing, the Microsoft of today has been humbled by the explosion of mobile and decline of the PC. But its recent moves with Office and wearables prove that the Microsoft of fifteen years from now will be much more interesting.