announced by Google earlier this afternoon, the apps are going to have a "material design" interface that is similar to the one used in the web browser version of Google Drive.
The updated Google Drive iOS and Android apps will have a new home screen that will not show the "quick access" panel at the top of the screen. The new home screen will simply show your latest files at the top in a linear view. The home screen also has a tab for Team Drives for those users who are part of a Team Drive. The search bar on the new home screen will be larger and prominent.
Another change to the Google Drive iOS and Android apps is found in the account switching function. In the new version you can simply tap on your profile icon in the upper-right corner of the app to switch between Google accounts.
The updated version of the Google Drive iOS app began rolling out today. The updated Android app for Google Drive will start appearing on March 18th.
These updates to the Google Drive mobile apps don't impact any of the functionality of Google Drive on iOS or Android. The updates should hopefully just make it easier to find and access the files that you need.
Screenshots courtesy of Google's outreach team.