Transitioning Universal Windows Platform (UWP) Apps to .NET 9
Microsoft’s evolution of Windows development frameworks has been a winding journey, culminating in today’s Windows App SDK and WinUI. While these modern tools offer improved capabilities for .NET desktop applications, updating older Universal Windows Platform (UWP) apps remains a challenge. Originally built on the Windows 10-era UWP model, many applications face compatibility and modernization hurdles, especially as UWP was designed around Microsoft’s early vision of a unified, store-driven application ecosystem.
The Universal Windows Platform emerged as an extension of the Windows Runtime (WinRT) model introduced with Windows 8. It provided developers with a framework to leverage new Windows APIs while integrating deeply with the Microsoft Store for distribution and monetization. However, its dependence on the Microsoft Store became a limitation, as it forced developers into a strict approval process and required them to use Microsoft’s payment platform. Over time, Microsoft recognized these constraints and gradually relaxed its policies, allowing Win32 applications, alternative payment systems, and broader distribution models.
With the upcoming release of .NET 9, Microsoft is introducing enhanced support for migrating UWP applications to the modern .NET ecosystem. This includes new tools designed to help developers transition their existing UWP codebases while benefiting from the latest .NET features. One of the most significant advantages of making the switch is the introduction of native Ahead-Of-Time (AOT) compilation, which can dramatically improve application performance and startup speed.
Native AOT compilation allows .NET applications to be compiled directly into platform-specific binaries, bypassing the traditional intermediate bytecode model. While .NET has long relied on just-in-time (JIT) compilation for flexibility across different architectures, AOT can optimize performance by generating precompiled binaries tailored for specific processor architectures, such as x64 and Arm64. This does require developers to generate separate builds for each architecture, but tools like Advanced Installer can help streamline deployment by creating multi-architecture installation packages. As .NET 9 nears release, these advancements provide a compelling reason for UWP developers to embrace the modern Windows App SDK and unlock the full potential of the .NET ecosystem.