One UI 9 is rolling out to the Galaxy S25, Fold7, and Flip7. Here is what to know before you tap install.

Two weeks ago I wrote about One UI 9 landing on the Galaxy S26. Then the S26's global rollout slipped, which I noted in my Android developer verification post. Now Samsung is moving down the lineup anyway, and last year's phones are getting the update. (Samsung)

Which phones are getting it

Starting September 28 in South Korea, stable One UI 9 based on Android 17 began rolling out to:

• Galaxy S25, S25+, and S25 Ultra, with the September 2026 security patch. (Android Authority)
• Galaxy Z Fold7 and Z Flip7, which only joined the One UI 9 beta earlier this month. (Android Authority)
• Galaxy S25 FE, S25 Edge, and Z TriFold, in a second wave the same day. (Sammy Fans)

Samsung usually starts in Korea and then works through other countries over the following days and weeks. There is no confirmed U.S. date yet, and carrier models in the U.S. tend to land after unlocked ones.

How big is it

If you are coming straight from Android 16 and One UI 8, the S25 download is close to 4 GB, about 3,851 MB. If you were in the beta, it is a small patch of around 535 MB. (Android Authority) The S25 Edge build was reported at about 3.4 GB. (Sammy Fans)

Before you tap install

• Check for it: Settings, Software update, Download and install.
• Back up first. A major version jump is the one update where a backup is worth the five minutes.
• Use Wi-Fi and a charger, and leave at least a few gigabytes free for the download and install.
• Give it a day or two. Battery life and app behavior often look off right after a big update while the phone re-indexes and re-optimizes apps. Judge it after that, not in the first hour.

Do not assume you get every S26 feature

The S26 launch list I covered included things like customizable Now Brief cards, Now Nudge, and the Interpreter thread view. In the coverage I read for this post, Samsung had not published a clear per device list of which Galaxy AI features come to older phones. Some heavier features may depend on newer hardware or need a Samsung account and an internet connection. Check the release notes on your own phone before you count on a specific feature.

For a sense of where this lands, my second line is a Galaxy Fold8, and it already runs One UI 9 on Android 17. It is also one of the two phones I test my Android app ports on, so I care about this rollout for a less exciting reason: every Galaxy phone that moves to Android 17 is one more phone my apps need to behave on.

Why this matters

Samsung promises seven years of OS updates for the S25 series, so this is the start of a long road, not the end. Updates like this are a good reason to hold onto a phone longer. If your S25 or Z7 works fine, the newest software is coming to you, and you do not need new hardware to get most of it.

Verified October 1, 2026. Rollout status changes daily, so check your own phone's Software update screen. The studio's app lineup is at jcmobileappstudio.com/apps.

Sources: Android Authority, SamMobile, Sammy Fans, SammyGuru, Samsung