Like the previous unlocked Samsung phones, unlocked Galaxy S9 and Galaxy S9 + are the latest for the party. The update of Android Pie has not yet arrived on either a single phone or a robust construction, even when all models of operators have been upgraded. continue to choose unlocked versions for different variations. You see, returning to the unlocked Galaxy S7 and Galaxy S7 Edge, Samsung has proven with every new unlocked message that they are in no hurry to update them. I've written a few articles about all this. I wrote that Samsung "hates" their unlocked phones as a whole does not manage to update them as they make variants of the carrier and they hit a handful of "finally" when they get big upgrades to the OS.
The S7 Edge update from Marshmallow to Nougat was 2-3 months later than carrier models. With the Galaxy S8 and Galaxy S8 +, waiting from Nuga to Oreo was shortened to a few weeks. So far with the Galaxy S9 and S9 +, we can be on schedule for such an implementation. All S9 models are upgraded from Oreo to Android Pie and Samsung UI, so we really are just waiting for unlocking.
It's hard to know for sure why Samsung has updated its unlocked phones last. These are phones that are always allowed to participate in beta versions, remember? My unlocked Galaxy S9 works from a UI and Android Pie from last November, but it's still on beta as carrier models that were not part of the test are on a stable pie. The same thing happened to the Galaxy S8.
Samsung's forum moderator said at one point that unlocked models might prove more difficult to update than carrier variants because they go through stringent tests for all networks they support. This kind makes sense, except they are always part of beta, as if it's easier to work with. How will you explain this?
Eventually we will probably see Android Pie and One UI in the US, unlocked the Galaxy S9 and the Galaxy S9 + within the next week or a few days. I can not imagine it will be much longer. But if you are unlocked by a Samsung phone owner because you like freedom and flexibility, understand that you can not always charge the fee in the software.