Samsung Accelerates One UI 9.5 Tests as One UI 9 Betas Expand

Early internal builds target current S26 phones and a likely S27 Ultra, signaling a faster release tempo for Samsung’s phone and watch software.

Overview

Samsung pushed the fifth One UI 9 beta for the Galaxy S26, S26+ and S26 Ultra on Wednesday with six fixes and the August security patch, available now in regions where the beta program is open.
Internal test‑server traces show One UI 9.5 builds linked to the Galaxy S26 lineup and to model SM‑S958U, which trackers identify as the unannounced S27 Ultra, indicating parallel development for current and next‑gen hardware.
One UI 9 Watch beta firmware for older models including the Galaxy Watch 8 Classic and Watch 7 has been uploaded to Samsung servers, while the Watch 9 and Ultra 2 already ship with One UI 9 Watch based on Wear OS 7.
Some watch test builds use a newer bootloader that can block downgrades and beta packages are unfinished, so early participants risk broken features, app crashes, and loss of the ability to revert to prior software.
The earlier‑than‑usual start to .5 testing suggests Samsung may bring public mid‑cycle betas sooner and could ship One UI 9.5 on next year’s S27, but public timelines and final feature availability for older watches remain unconfirmed.