This is a very important milestone for the client as it faces stiff competition on Android. Indeed, Google installs its hugely popular Gmail app by default on the platform. Sure, Gmail is the leading email service, but Outlook clearly has its audience.
As we move into the new year, we do so without Windows Phone. Microsoft's mobile platform has been killed off, leaving its users migrating to Android or iOS. More of those users should be pushing for Microsoft services on those platforms.
As mentioned, 100 million is a massive number and shows Outlook's success. However, in terms of popular apps, it's actually a modest figure. Certainly, Microsoft has more popular apps, such as SwiftKey with over half a billion installs, and Skype with over 1 billion.
Still, Outlook's numbers show the app is a roaring success and remains a favorite amongst business users. It is also worth noting that the 100 million installs is Android specific and does not count iOS downloads.
In October, Microsoft added more functionality for business users with deeper Office integration.
Specifically, Outlook on Android now supports Actionable Messages. With this tool, users can complete Microsoft Office tasks directly within an email without leaving the app. Microsoft has added buttons on email winders to help people interact with Office.
Microsoft explains in its release notes how the feature works:
“Get more done without leaving your inbox! Outlook for Android now supports Actionable Messages for emails from Microsoft Flow, SharePoint, MyAnalytics, and more. You'll see buttons in the body of supported messages that let you take action in context. (Office 365 and Outlook.com accounts)”