Updated June 16 with more details of the new software and why the second version of the beta has been released.

Apple announced the latest iPhone software, iOS 26, on Monday, June 9. The first release for developers came later the same day. Just three days later, Apple released a second build of the first beta — that’s unprecedentedly soon. And it’s now become clear that one of the most anticipated features coming to iOS 26, smart storage, is in the first beta. Apple has now told us exactly why the first beta was re-released. More on both these topics below.

Almost always, there’s no update to the first release until the second beta in late June or early July, and that routinely arrives at least two weeks after the first developer beta (while the first public beta is scheduled for July). So, what’s going on?

The update that’s quietly arrived is only for iPhone 15 and iPhone 16 series models. So, iPhone 14 and earlier users won’t see the update for their developer betas.

To check, follow the usual route towards software updates: open Settings, choose General and then Software Update. You need to be a registered developer, of course.

The old build number was 23A5260n and that moves to 23A5260u with this update. In other words, this is a new build of the first beta, not the second developer beta.

Nevertheless, it’s worth updating to it if you’re offered it.

Apple has not revealed what the differences are between the two builds, though some think it’s about the battery life, for instance Juli Clover at MacRumors. “The revised beta addresses an issue that could cause some iPhone 15 and iPhone 16 models to show a low battery symbol and be unable to start up after updating to the initial iOS 26 beta,” Clover reports.

Other analyses suggest something different, like Ryan Christoffel at 9to5Mac, suggests that “Apple discovered a crucial bug or security issue—or perhaps code that leaked future products—and felt it necessary to push a new build,” the report says.

That reference to future products concerns code in the first beta which mentioned AirPods Pro 3.

In the past, if your iPhone storage was almost full, it turned out to be a problem when you came to update. If there was not enough room to install the update, the user might find they had to delete content to avoid a failed update error.

As WCCFTech points out, this could be a thing of the past. “With iOS 26, Apple is proactively addressing this by reserving space ahead of time when automatic updates are enabled in the Settings app,” the report says.

We don’t yet know how this dynamic reservation of space will work, or how much will be automatically be set aside, but it may “align with similar mechanisms in macOS. If you are not familiar with it, Apple already uses temporary system storage management during updates, even in the case of iOS, but the new feature could mean that the system actively manages and holds onto space as part of its background maintenance,” the report adds.

However it works, reducing friction for updates can surely only be a good thing.

So, why did Apple take the unusual step of re-releasing the first beta? In the Feedback app which is part of the developer beta experience, Apple has commented that there is a resolved issue in the new update.

“Fixed: Some iPhone 15 and iPhone 16 models might show a low battery symbol and be unable to start up after updating to iOS 26 beta 1,” it reads. It looks like the re-release has sorted the issue which, for some users of the very first beta required a full restore of the operating system.

The initial responses to iOS 26 developer beta have been mixed. For instance, some users have said that the new Liquid Glass design makes notifications hard to read — though other users say this is purely down to the wallpaper behind, not the new design.

Some users have been delighted that with iOS 26 it’s possible to install beta updates on AirPods for the first time. Others have commented on the phone getting hot and the battery running low, though these are not uncommon with early beta releases. Some users have found that their banking app didn’t open (again, not unusual in such an early beta) and others have given up and downgraded to iOS 18.5.

As a postscript, this beta should not be installed on your main iPhone as at this stage it’s too much to expect for it to be glitch-free.