Microsoft first launched Outlook Lite as a smaller app for Android devices in 2022, at the height of an industry focus on lightweight mobile apps. It was designed to be faster, use less battery, and work well across 2G and 3G networks. Microsoft now says it will fully retire Outlook Lite on May 25th, disabling mailbox access but still allowing the app to launch. It’s time to switch to the regular Outlook app if you’re still relying on Outlook Lite.