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Run iPhone 12 on iOS 4 with the OldOS app to see how tough your forbearers had it

By Daniel Petrov

Updated: Jul 06, 2021, 5:16 AM

Run iPhone 12 on iOS 4 with the OldOS app to see how tough your forbearers had it

Counterintuitively, all things retro a cool nowadays. Monochrome watches from the 80s, vintage sneakers, vinyl, you name it. In line with the times, a young developer has made it cool to rock your iPhone 12 on... iOS 4.

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Apple's venerable mobile operating system version that first debuted way back ten years ago, marking the first numbered escape from the iPhone OS titling scheme, has been lovingly recreated in the form of an app by Zane, using the modern SwiftUI coding that ensures full compatibility.

Today is Launch Day

Introducing OldOS — iOS 4 beautifully rebuilt in SwiftUI.

* Designed to be as close to pixel-perfect as possible.
* Fully functional, perhaps even usable as a second OS.
* ️ Fully open source for all to learn, modify, and build on. pic.twitter.com/K0JOE2fEKM
— Zane (@zzanehip) June 9, 2021

The "skeuomorphic" design is all here, as is the old version of Safari, and the only major issues are, surprise, with the YouTube and Messages apps that Apple used to bundle with iOS directly.

Called OldOS, the app that runs your retro iPhone looks is available to grab from Apple's Testflight service, so get it while you can if you are interested, before Apple has gotten a whiff of this blast from the past playground. The developer has made it open source, though, for everyone to contribute, so the OldOS project might live on and play whack-a-mole with Apple's rules and regulations for the foreseeable future.

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Daniel, a devoted tech writer at PhoneArena from 2010 to 2025, has been engrossed in mobile technology since the Windows Mobile era. His expertise spans mobile hardware, software, and carrier networks, and he's keenly interested in the future of digital health, car connectivity, and 5G. Beyond his professional pursuits, Daniel finds balance in travel, reading, and exploring new tech innovations, while contemplating the ethical and privacy implications of our digital future.