Google has updated the Gmail app for Android to version 5.0 and has completely overhauled it, both visually and under the hood. The new app sports a user interface abiding to the Material Design standards, even on pre-5.0 devices.
The big functional change is that the Gmail app now supports 3rd party email accounts with POP and IMAP. This means you can add your Outlook, Yahoo or custom work email without any problems and eliminate the need for a separate app.
Check out the promo video Google has made for the latest version of Gmail.
As per usual, the update is rolling out gradually and you should be on the lookout to receiving it in the following days.