The Galaxy Watch 4 and Watch 4 Classic smartwatches will definitely receive the next One UI 8 Watch software update. It will receive almost all the features that have been introduced in Wear OS 6. Further, it will also get Samsung Health features like Running Coach, Vascular Load, Antioxidant Index, and many more. It will be the last major software update for the smartwatch. After that, the Galaxy Watch 4 series will not get One UI 9 Watch or later versions.
Also, don’t expect the One UI 8 Watch beta testing program for these watches. Samsung has confirmed that the beta program will be open only for Galaxy Watch 5 and newer Galaxy Watches. To use new software, you may have to wait a few more months till the beta program ends.