After digging through iOS 27, I found that the foldable iPhone has been quietly "officially announced"

Although iOS 27 is still in its first developer preview, it has already been recognized by the APPSO editorial team as "the most exciting iOS in five years."

Compared to Siri AI, undoubtedly, the September iPhone autumn launch event will have a greater impact on us.

According to the most widespread leaks, the release schedule of the iPhone 18 series will be very different from previous years.

More specifically, it will be split into two launches, one in autumn and one in spring:

• September 2026: Release of the iPhone 18 Pro/Pro Max and the foldable iPhone Ultra
• March/April 2027: Release of the standard iPhone 18 and the iPhone 18e

Image | 9to5Mac

Undoubtedly, the most exciting and anticipated product update is the foldable iPhone Ultra —

After all, even though Siri was two years late, the edge-lit UI still became an industry standard.

Even if the foldable screen is seven years late, who knows, it might lead other manufacturers to "reinvent the foldable screen"?

All currently known information indicates that the iPhone Ultra will be a product with a "wide fold" form factor that unfolds into a landscape screen.

It will most likely feature a rectangular + rounded-corner body similar to the Pixel Fold, as well as a dual-camera setup with a main camera and an ultra-wide-angle camera:

However, there are various speculations about the software aspect of the iPhone Ultra. There are rumors that it could turn into macOS when unfolded, simply copy iPadOS, or have a dual iOS setup.

It wasn't until WWDC 26 that the details of iOS 27 truly revealed the existence of the foldable iPhone.

The Return of the Wide Screen

In the past few major versions of iOS, although Apple rarely explicitly stated it, you must have felt a change:

The landscape mode on the iPhone has become increasingly less user-friendly.

This change started in 2020 with iOS 14, when Apple removed the "Home screen rotation" feature, locking both full-screen and non-full-screen models into a "portrait-only" world.

Image | PhoneArena

Subsequently, Apple made more changes, gradually removing the landscape mode from many system interfaces and apps. This trend continued until iOS 26.

However, in iOS 27 Developer Beta 1, you'll notice that many system apps that previously didn't (or no longer) support landscape mode have suddenly added landscape interfaces —

The above are all apps that didn't support landscape mode in iOS 26 but do in iOS 27

The changes to the Weather and Music apps are particularly noticeable.

The former not only supports landscape mode again but also has a specially designed layout for the information section in landscape orientation:

The highly anticipated landscape mode for the music playback interface has also changed from being exclusive to StandBy to a landscape player that can be used at any time:

Considering that in various leaked materials and rumors, the inner screen of the iPhone Ultra has an aspect ratio of approximately 1:1.41, it's not surprising that various system apps are adapting to landscape interfaces in advance.

Corroborating this is that in the iPhone mirroring feature of macOS 27, we can not only adjust the window size but also the aspect ratio.

At this time, some apps that don't support wide aspect ratios on the iPhone also show adaptation to landscape mode:

What's even more interesting is that the wide-screen layout of the Weather app in mirroring mode is different from the iPhone's landscape mode.

This aspect ratio is so wide that it's almost close to a triple-fold screen:

In addition, with the update of Xcode 27, some developers have discovered new parameters related to the foldable screen in the iOS 27 codebase.

According to developer Sam Henri Gold, several new parameters named foldState (fold state) and angleDegrees (fold angle in degrees) have been added to the iOS 27 system:

Image | X @samhenrigold

The private API MobileGestalt, which is used for internal device information queries in iOS, has also added a very special parameter in iOS 27:

_MGGetLogicalDeviceDisplayCount (Get the number of logical screens on the device)

What makes this new parameter special is that, unlike parameters like UIScreen.screens.count, which represent the "number of available displays," its naming is more related to the device's own display configuration —

Obviously, this refers to the inner and outer screens of the iPhone Ultra.

Image | YouTube @fpt.

Official Certification: PSotU

Anyway, the above are just some details in the iOS 27 Developer Beta. Strictly speaking, they don't count as Apple's official recognition of the foldable screen.

So, was there a more authoritative announcement at WWDC? The answer is yes.

Image | YouTube @Apple

People usually only pay attention to the opening ceremony of WWDC, but many don't know that there are two speeches on the opening day of WWDC, not just one.

In addition to the keynote speech by the CEO, there is also a speech for developers —

The WWDC Platform State of the Union (PSotU).

Image | Youtube @Apple Developer

"State of the Union" is a term in the US Constitution, referring to the "State of the Union Address" submitted by the President to Congress.

In contrast, Apple's Platform State of the Union (PSotU) is actually a highly concentrated overview.

Its purpose is to comprehensively introduce the features and technical details that couldn't be covered in the keynote speech and to provide guidance for the sessions during WWDC.

The new specifications and APIs that appear in the PSotU and sessions are the real things "endorsed by Apple" and prepared for the foldable iPhone.

Image | Apple Developer

First of all, Apple has clearly stated its support for dynamic size adjustment of iOS apps:

This year, we will support size adjustment of app windows when using iPhone mirroring on Mac and running iOS apps on iPad.

That means in the latest SDK, as long as an app is based on SwiftUI, it can automatically adapt to different display layouts:

Image | Apple Developer

More importantly, in this year's PSotU, Apple officially called on developers:

Instead of designing layouts specifically for device models and orientations, you should design app layouts for a range of different sizes and aspect ratios.

The most obvious change is in the toolbars of iOS apps —

Since the size of app windows is no longer fixed, developers should no longer limit the number and width of toolbar items.

Instead, they should set the hierarchy and order of buttons and determine which buttons should always be displayed:

Image | Apple Developer

At first glance, this change seems to be aimed at macOS 27 and iPadOS 27, but upon closer inspection, it is also paving the way for the multi-window mode of the foldable screen and the display specifications for the inner and outer screens.

In macOS 27 and iPadOS 27, Apple has also optimized the design and rendering of the sidebar.

This change mainly addresses the issue in macOS 26 where the liquid glass effect of the sidebar blended too well with the background color, making it difficult to distinguish different levels: