Samsung Begins One UI 8 Internal Testing for Galaxy Z Flip 4 and Z Fold 4 – Stable Update Coming Soon!

Naveen Thakur

2 Aug, 2025

Samsung Enters Final Phase of One UI 8 Rollout

Samsung’s One UI 8 journey is moving into its final and most exciting stage. The tech giant has been diligently testing the Android 15-based One UI 8 on its latest devices for months. But now, attention has turned to older but still widely used foldables—the Galaxy Z Flip 4 and Galaxy Z Fold 4. Internal testing builds for both devices have just been spotted, signaling that Samsung is preparing to bring One UI 8 to these foldables very soon.

One UI 8 testing Galaxy Z Flip 4 Fold 4 – Internal firmware builds for Android 15 update

In this blog, we explore what this internal testing means, what firmware has been spotted, how it fits into Samsung’s update strategy, and what users of the Galaxy Z Flip 4 and Fold 4 can expect from the upcoming update.

One UI 8 Internal Testing Begins for Galaxy Z Flip 4 and Fold 4

Samsung has officially begun internal testing of the One UI 8 firmware on its 2022 foldables. The following firmware builds have appeared on Samsung's internal server:

Galaxy Z Flip 4: F721NKSU6IYGD
Galaxy Z Fold 4: F936NKSU6IYGD

These builds are being tested on the South Korean variants of both models, typically the first to receive major software updates due to Samsung's home market prioritization.

The presence of these internal builds strongly suggests that Samsung is in the final phases of development for the One UI 8 stable update, and a public rollout may begin sooner than expected.

Why This is Big News for Flip 4 and Fold 4 Users

The Galaxy Z Flip 4 and Z Fold 4, though released in 2022, continue to be popular devices among foldable phone enthusiasts. With One UI 8 testing now underway, users can expect:

A fresh Android 15 experience
Enhanced performance and animations
Better foldable-specific features
Battery optimizations
More customization options

Since these devices already run One UI 7 based on Android 14, the One UI 8 update will mark their second major OS upgrade, out of the four they are promised.

Samsung’s Update Strategy: All Eyes on Speed and Scale

Samsung’s current approach to software updates is both aggressive and strategic. The company is testing One UI 8 on several devices simultaneously, including:

Galaxy S25 series (Beta 4 already released)
Galaxy Z Flip 6
Galaxy Z Fold 6
Galaxy S24 series
Galaxy S23 series
Galaxy A56
Galaxy Z Flip 4 & Fold 4 (now confirmed)

This wide-scale internal testing strategy hints that Samsung plans to roll out One UI 8 updates to multiple device generations at once, starting from the latest flagships and working its way to older models quickly.

What Does This Mean for Galaxy Z Flip 4 & Fold 4?

Samsung’s move to begin testing internally before launching public beta programs means the company could skip the beta program entirely for older models and go directly to stable rollout—especially if the internal builds pass QA checks quickly.

Galaxy Z Flip 4 & Fold 4 One UI 8 Update Timeline – What to Expect

Although Samsung hasn’t officially announced the One UI 8 release date for the Galaxy Z Flip 4 and Fold 4, we can make a reasonable estimate based on previous patterns.

Device	Internal Testing Detected	Estimated Public Rollout
Galaxy S25	Beta 4	Early August 2025
Galaxy S24	Internal	Mid-to-Late August 2025
Galaxy Z Flip/Fold 6	Internal	August-End / September 2025
Galaxy Z Flip 4	Internal	September 2025
Galaxy Z Fold 4	Internal	September 2025

Expect the stable One UI 8 update to arrive for Flip 4 and Fold 4 in September 2025, starting in South Korea, then expanding to Europe, India, and the US in the following weeks.

Features to Expect in One UI 8 for Galaxy Foldables

While Samsung hasn’t officially released the changelog for One UI 8 on older foldables, we can safely assume it will include many features from the S25 beta, as well as foldable-specific enhancements.

Key Android 15 Features Likely Included:

Privacy dashboard improvements
Lock screen shortcuts customization
Notification permission enhancements
Partial screen sharing
More granular battery usage reports

Foldable Enhancements:

Optimized Flex Mode functions
Better app continuity across folded/unfolded states
Improved multitasking support
Battery performance tweaks for dual-screen use

These changes aim to make the foldable experience more seamless and productive, especially for power users who rely on multitasking.

What Should Flip 4 and Fold 4 Owners Do Now?

If you own a Galaxy Z Flip 4 or Z Fold 4, here’s what you can do to get ready for One UI 8:

Back Up Your Data: Use Smart Switch or Samsung Cloud to secure your data before major updates.
Free Up Space: Major firmware upgrades require at least 5–10GB of free space.
Keep Battery Charged: Ensure your phone has more than 50% battery when installing the update.
Check for Beta Participation (If Offered): While unlikely, keep an eye on Samsung Members app in case Samsung opens a beta window.

Samsung Galaxy Software Support – A Shining Example

Samsung continues to be a leader in Android software updates. The company offers four years of major OS updates and five years of security patches for its flagship and upper mid-range devices.

With One UI 8 based on Android 15, the Z Flip 4 and Fold 4 will still receive two more major OS upgrades (Android 16 & 17), making them long-term devices worth keeping.

Want to be the first to know when One UI 8 goes live for your device?

🔔 Bookmark Ask Anything

While internal testing is ramping up for older models, Samsung has already released One UI 8 Beta 4 for its Galaxy S25 series, suggesting a stable release is just around the corner for flagship owners.

If you own a Galaxy S25, S25+, or S25 Ultra, you might want to check the Samsung Members app today—you may receive the final beta or even the stable version depending on your region.

Final Thoughts: One UI 8 is Closer Than Ever

Samsung is clearly on track to deliver One UI 8 across its entire Galaxy ecosystem within the next few months. The internal builds for Galaxy Z Flip 4 and Fold 4 show that Samsung is preparing for a widespread stable rollout of Android 15-based One UI 8.

Whether you're a foldable phone user or flagship enthusiast, Samsung’s update game remains unbeatable in the Android world.

Stay tuned to Ask Anything for fast One UI 8 coverage, changelog breakdowns, and OTA rollout timelines!

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