Duo Mobile 4.0.0
Duo Mobile has had an update, resulting in the new changes to the design and functionality. One change that took place between version 3 and version 4 is that the buttons to approve or deny a push authentication have swapped.
Other differences come as user interface design changes and other things that can be found in the video below and at the Duo Mobile official article.
These changes are a part of the new Version 4.0.0 Duo Mobile update.