iOS 27 beta 4 is now available to registered developers, bringing another round of refinements to Apple’s next major iPhone update. The build adds useful options for Siri, Photos, Apple TV downloads, AirPods controls and professional video while addressing some of the rough edges seen in earlier testing.
This is still pre-release software—not the finished iOS 27 update expected later in 2026. Here is what changed, which iPhones can test it and whether everyday users should install it.
What is iOS 27 beta 4?
Apple released iOS 27 developer beta 4 on 20 July 2026 with build number 24A5390f, as listed on the Apple Developer releases page. It follows the first iOS 27 public beta and continues Apple’s testing cycle ahead of the full release.
Apple’s official iOS and iPadOS 27 beta release notes remain the best reference for documented bugs, resolved issues and developer-facing changes. Features can be revised or removed before the final version.
iOS 27 beta 4: the key changes
More Siri controls and interface refinements
Beta 4 adds a short introductory screen when users open the Siri Search or Ask interface. A new preview setting also controls how many lines appear in Siri app conversation lists, much like preview options in Mail.
Accessibility gains an “Always Show Request” option that can keep a transcription of a spoken Siri request visible on screen. Siri’s voice-selection interface has also been adjusted, with additional voice and customisation options appearing on supported devices. Availability can vary by iPhone model, language and region.
Automatic downloads in the Apple TV app
The Apple TV app now includes an Automatic Downloads option. According to MacRumors’ beta 4 testing, enabling it downloads the next two episodes of a programme in Continue Watching, then removes completed episodes. That could be helpful for commuters and travellers who do not want to manage downloads manually.
A new Photos display option
A “Zoom Photos to Fill” toggle appears in Settings for the Photos app. It slightly enlarges images whose proportions are already close to the iPhone display, reducing unused space around the picture. The setting is enabled by default, but users who prefer to see every edge can switch it off.
AirPods Adaptive mode controls
Apple has refined the appearance of AirPods controls in Control Centre. Compatible AirPods Pro models also receive a more detailed Adaptive mode control, making it easier to adjust the balance between environmental awareness and noise reduction.
ProRes Log 2 video encoding
On supported Pro iPhones, the Camera settings can now offer a choice between Log and Log 2 when Apple ProRes is enabled. Log 2 is designed to retain more image information for greater flexibility during colour grading. This is primarily useful for filmmakers and serious video creators; the larger files and extra post-production work make it unnecessary for most everyday recording.
Why the iOS 27 beta 4 changes matter
This build is less about one headline feature and more about making iOS 27 feel complete. Automatic TV downloads solve a practical offline-viewing problem, the Photos toggle gives users more control, and the Siri options improve readability and accessibility. Better AirPods controls and expanded ProRes settings also show Apple polishing experiences across its hardware ecosystem.
iOS 27 itself is a larger update centred on Apple Intelligence, an upgraded Siri experience, design refinements and quality-of-life improvements. However, Apple Intelligence and some advanced Siri features require newer hardware. The general iOS 27 compatibility list is broader, covering iPhone 11 and later plus the second-generation iPhone SE and newer, according to current beta reporting.
What about the dual-battery iPhone references?
Testers have found code strings in beta 4 that appear to describe an iPhone containing more than one battery. This has prompted speculation about a future foldable iPhone, but it is not a product announcement. Code references can support prototypes, internal testing or products that never ship.
Apple has not confirmed a dual-battery or foldable iPhone through this beta. Treat the finding as a rumour and not as evidence of a launch date, product name or final design.
Should you install iOS 27 beta 4?
Most users should wait for the finished public release. Beta software can cause faster battery drain, crashes, connectivity problems and incompatibility with banking, work or authentication apps. Even a relatively polished build can have bugs that only appear with particular accessories or usage patterns.
If you are a developer or experienced tester, install it on a spare compatible iPhone where possible. Make an encrypted computer backup or a current iCloud backup first, check that essential apps work with the beta, and keep enough free storage for the update. You can find Apple’s beta controls under Settings > General > Software Update > Beta Updates when the device is enrolled with an eligible Apple Account.
Readers considering the broader test release should also see our iOS 27 public beta guide. For context on the stable update preparing current iPhones for the next generation, read our iOS 26.6 RC explainer.
Final thoughts
iOS 27 beta 4 is a measured but useful update. Siri interface improvements, smarter Apple TV downloads, Photos controls, AirPods refinements and ProRes Log 2 make the beta more capable without changing its essential status: it is test software. Everyday users will get the safest experience by waiting, while developers can use this build to test apps and report issues before launch.
FAQs
Is iOS 27 beta 4 the final iOS 27 release?
No. It is a developer beta and Apple can change features, performance and compatibility before the public release.
What is the iOS 27 beta 4 build number?
Apple lists iOS 27 developer beta 4 as build 24A5390f.
Which iPhones support iOS 27?
The current beta supports iPhone 11 and newer models, along with iPhone SE (second generation) and later. Advanced Apple Intelligence and Siri features may require newer hardware.
Is it safe to install on a primary iPhone?
It is not recommended for most people. Bugs, reduced battery life and app compatibility issues can disrupt a primary device.
Can I leave the iOS 27 beta programme later?
You can turn off Beta Updates to stop receiving new beta builds. Returning immediately to the latest public iOS version can require erasing and restoring the iPhone, so make a suitable backup before installing.
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