I have now been on this Android 14, One UI 6.0 beta for 5 days and I find it to be the most complete beta that I have ever tested. I have come across no major issues and the two 3rd party apps of mine that did not behave correctly were down to the app developers not having updated them for Android 14.
The lack of feedback and error reports on the Beta section of the Samsung Members app, (now just called Members), for beta would seem to bear this out.
One of the reasons I believe that the Fold5 beta is so complete is that the earlier 5 or 6 S23 betas have already done the heavy lifting prior to the Fold5 beta release.
I have seen stable roll-outs on firmware much less rounded and stable than this in the past. It would not surprise me if there was only one other or perhaps none, before a stable release is announced.
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My device... Galaxy Z Fold5 5G 12/512GB (G946B D/S) CSC EUX. Android 14. One UI 6.1
