Samsung’s One UI, which is their new UI based on Android Pie, began rolling out in beta form a few weeks ago. One UI is the biggest design change we’ve seen from Samsung software in a very long time. One UI has a focus on one-hand usability and adds a system-wide dark mode, among other things. The third beta of One UI is rolling out now to the Samsung Galaxy S9.
The third beta of One UI is software version ZRL5 and comes in at 589.27 MB. It includes the December security patch and a number of bug fixes. As this is a beta, there are obviously a lot of things to be ironed out. Some of the issues fixed include the dialer freezing, Samsung Pass login issues, alarms not working, Home and Back button not working in Recent Apps, auto wake-up not working, and a bunch more.
The screenshot below is from Reddit user DJZeroGrav and you can see the full changelog. This is available for the Galaxy S9 and Galaxy S9+.