Samsung Galaxy S7 owners will be getting an update that brings the new Samsung Experience UI found on the Galaxy S8 family and the Galaxy Note 8, according to an admin over at the Samsung Community forums. When user Drago asked about the Galaxy S7 getting Bixby and the new UI, an admin clarified that Bixby will not be making its way to the Galaxy S7, but that the 2016 flagship will be getting the newest version of Samsung's custom Android user interface in its next update. The forum admin did not outright state that the update in question is also the update to Android 8.0 (Oreo), or when the update would come. While it's not entirely unfeasible to assume that Samsung will throw the new UI on top of Android 7.0 (Nougat) while users are watching for signs of an Oreo update, such an approach would be counter-intuitive, to say the least.
The Galaxy S7 and Galaxy S7 Edge did get a UI update to the Samsung Experience when they got Nougat, but this was the very first version of the UI, meant to correct pain points with TouchWiz and introduce some new features. Since that release, some bumps have been smoothed out and some features have been added in. As for Bixby, there is no real hardware-related reason that it could not be ported to the Galaxy S7, though future features that take advantage of onboard machine learning will not work - that processor feature is only in the current generation, including the Qualcomm Snapdragon 835 and Samsung Exynos 8895, albeit with different implementations. In any case, the Qualcomm Snapdragon 820 and Samsung Exynos 8890 do not have any sort of onboard AI and machine learning features.
The newest version of Samsung's custom UI cures most of the ills of TouchWiz that had left users unimpressed. Namely, it cleans up the interface significantly, banishes lag almost entirely, and takes on a whole new, cleaner, more aesthetically basic look that's light and pleasing, but also lends itself very well to Samsung's built-in theming solutions. Moving forward from the first version of the Samsung Experience, the new version does a bit more cleaning up of the UI, changes the settings menu a bit, and runs a bit leaner on RAM, which means more speed.