The OldOS Project is a recreation of iOS 4 built almost entirely in SwiftUI that runs on modern devices.
The project recreates the user experience of iOS from a decade ago by implementing a pixel-perfect visual design paired with functional integrations to the device's actual data and services. Most built-in apps work with live data: the iPod app plays music from your library, Maps provides real directions, Safari browses the web, and Weather displays current conditions. Beyond individual apps, the system includes functional settings, home screen customization, app search, and lock screen functionality. The approach merges historical interface design with contemporary iOS frameworks to deliver what the creator describes as a usable second operating system rather than a static emulator.
This project suits developers interested in learning SwiftUI through a substantial, real-world codebase or those nostalgic for early iOS design who want a working recreation on their current device. The entire codebase is open source and structured for learning, with apps organized into separate files and a Common file containing reusable UI components built as bases for customization. The creator explicitly positions it as a teaching tool to demonstrate SwiftUI's capabilities and how iOS itself works. Anyone considering adoption should understand that some apps remain incomplete, though the creator indicates they are planned for future releases.
Development activity shows the project was revived after a significant hiatus, with a major version update that retooled the codebase for modern devices and resolved compilation issues with current Xcode versions. The project maintains clear documentation through inline code commentary and a logically organized file structure designed to be accessible to developers learning from the source.
