Another Monkey: Analysis of the Mono Project History and Future Based on Microsoft Announcement

“You must have heard tales about him. Some say he helped Tang Monk fetch the Scriptures, was granted Buddhahood, and stayed on Mount Lingshan thereafter. Some say it was not him who was granted Buddhahood. The real him was already dead on the journey to the West. Some say the journey never happened. He’s nothing but a monkey who lives in some storyteller’s tall tale. But now, you will hear a tale which no one has ever known.” — Black Myth: Wukong

Recently, Black Myth: Wukong has created a buzz worldwide. However, this article doesn’t focus on this Chinese mythical hero, nor the Destined Ones, but on another “monkey” that once made waves in the tech world, the Mono Project—an open-source implementation of Microsoft’s .NET Framework that allowed developers to build cross-platform applications.

A few months after the Mono Project’s GitHub repository stopped receiving updates, Microsoft finally released an important announcement. Combining insights from the historical context recorded in .NET Legend, this article will analyze and interpret the contents of this announcement step by step, exploring the role that the Mono Project has played in technological evolution and what this announcement means for its future.

Sentence 1

“The Mono Project (mono/mono) (‘original mono’) has been an important part of the .NET ecosystem since it was launched in 2001.”

The announcement starts with a minor historical inaccuracy. While Microsoft references 2001, the Mono Project was actually initiated in 2000 (with its first public release in 2001). As detailed in The .NET Legend, the Mono Project was initiated and led by Miguel de Icaza with the aim of introducing .NET framework-related technologies to the Linux platform, enabling the rapid development of applications on Linux. Mono provided a C# compiler, a Common Language Runtime (CLR) compatible with Microsoft’s implementation, and a set of class libraries that allowed developers to write and run .NET applications on platforms beyond Windows.

Like its name suggests, the Mono Project is like a nimble monkey, helping developers move freely between different platforms and providing immense convenience.

Sentence 2

“Microsoft became the steward of the Mono Project when it acquired Xamarin in 2016.”

The golden age of the Mono Project was also the years when it powered the Unity gaming platform and the Xamarin mobile development platform, serving a vast number of developers. Unity used Mono as its scripting backend, enabling game developers to write C# code that would run across multiple platforms. Similarly, Xamarin leveraged Mono to let developers build mobile applications for iOS and Android using C# and .NET.

Microsoft became the steward of the Mono Project in 2016 through its acquisition of Xamarin. This marked a new phase in Mono’s development and represented a significant shift in Microsoft’s approach to open-source and cross-platform development. Before and after the acquisition, Microsoft integrated Xamarin with the .NET Framework/.NET Core ecosystem in the first round, offering developers using .NET/Mono technology an improved experience.

Sentence 3

“The last major release of the Mono Project was in July 2019, with minor patch releases since that time. The last patch release was February 2024.”

2019 was a pivotal year for the .NET ecosystem. The official release of .NET Core 3.0/3.1 and the announcement of the .NET 5 development plan marked a significant acceleration in the modernization of the entire .NET platform, entering a second phase of deep integration. This greatly affected the importance of the Mono Project. As .NET Core gradually became mainstream, the marginalization of Mono became inevitable. Although the sudden emergence of Blazor indicated that part of Mono’s core technology—specifically its WebAssembly capabilities—was something .NET Core lacked at that time, the announcement of .NET 5 made it clear that the .NET ecosystem was moving towards a unified platform.

Although the Mono Project underwent its last major update in 2019, subsequent development work focused mainly on fixing bugs and releasing minor patches, rather than introducing new features or improvements. The last patch version of the Mono Project under Microsoft’s management was released in February 2024, coinciding with the final days of the Xamarin brand within Microsoft’s products. After May 1, 2024, the Xamarin brand officially exited the historical stage, fully replaced by .NET MAUI.

Sentence 4

“We are happy to announce that the WineHQ organization will be taking over as the stewards of the Mono Project upstream at wine-mono / Mono · GitLab (winehq.org). Source code in existing mono/mono and other repos will remain available, although repos may be archived. Binaries will remain available for up to four years.”

In its announcement, Microsoft stated that the management of the Mono Project would be transferred to WineHQ, marking a new historical stage for the project. For context, WineHQ is best known for developing Wine (“Wine Is Not an Emulator”), which allows Windows applications to run on Unix-like operating systems. Wine has been instrumental in enabling cross-platform compatibility for Windows software, making it a logical steward for the Mono Project.

With the steady advancement of .NET 5/6/7/8/9, the vast majority of developers have already completed their project migrations from Mono to the unified .NET platform. However, there are still numerous legacy applications and specialized use cases that rely on Mono’s unique capabilities.

The Mono Project has been handed over to an organization dedicated to open-source and cross-platform compatibility. But what value can this project continue to provide under WineHQ’s stewardship? Despite the challenges of limited resources and accumulating technical debt, WineHQ may bring new vitality to the Mono Project, particularly in scenarios where Wine needs to run .NET applications designed for Windows.

Fun fact: Gamers enjoying Black Myth: Wukong on Apple’s M2 hardware are likely benefiting from the efforts of WineHQ’s Wine project, which powers compatibility layers like CrossOver that make Windows games playable on macOS.

Sentence 5

“Microsoft maintains a modern fork of Mono runtime in the dotnet/runtime repo and has been progressively moving workloads to that fork. That work is now complete, and we recommend that active Mono users and maintainers of Mono-based app frameworks migrate to .NET which includes work from this fork.”

During the .NET 5/6 era, Microsoft integrated Mono’s most valuable asset, MonoVM, into the .NET ecosystem. This integration fostered the healthy development of Blazor and .NET MAUI. The currently active version, .NET 8, and the upcoming .NET 9 are the modern, unified .NET platform that all developers rely on.

Microsoft’s advice is clear: for most developers, focusing on .NET 8 is sufficient, rather than on Mono. The modern .NET platform incorporates the best parts of Mono while offering improved performance, better tooling, and continued support.

Sentence 6

“We want to recognize that the Mono Project was the first .NET implementation on Android, iOS, Linux, and other operating systems. The Mono Project was a trailblazer for the .NET platform across many operating systems. It helped make cross-platform .NET a reality and enabled .NET in many new places and we appreciate the work of those who came before us.”

Here, Microsoft highly praises the Mono Project, especially its pioneering role in cross-platform development. Mono was the first implementation of .NET technology on non-Windows platforms. Its contributions in recent years have helped Microsoft’s .NET ecosystem reach more operating systems and devices, achieving today’s mainstream development platform status. The historical contribution of the Mono Project cannot be overlooked, as I’ve similarly concluded in The .NET Legend.

Conclusion

The history and future of the Mono Project are a microcosm of the development of the .NET ecosystem. From Miguel de Icaza’s personal endeavor to Microsoft’s acquisition, and finally to its transfer to WineHQ, each phase of the Mono Project has held different significance. The release of .NET 5/6/7/8/9 signifies that the historical mission of the Mono Project has been largely fulfilled, though specialized use cases will continue to benefit from its existence. The future of the mainstream .NET ecosystem will increasingly depend on the development of Microsoft’s unified .NET platform.

WineHQ representatives have indicated that they are planning and researching the next phase of the Mono Project’s development and hope to reveal more details soon. I will continue to follow the future of the Mono Project closely.

What’s Next?

If you’re a developer currently using Mono for your projects, now is a good time to evaluate your migration strategy to modern .NET. Microsoft provides comprehensive migration guides to help with this transition. For specialized use cases where Mono remains necessary, keeping an eye on WineHQ’s development roadmap will be crucial.

What are your thoughts on this transition? Have you been a Mono user, and if so, how has it impacted your development workflow? Share your experiences in the comments below.

As for the connection between Black Myth: Wukong and the Mono Project, perhaps I’ll find another opportunity to write a special article about it. Both represent journeys of adaptation and transformation in their respective domains—one in mythology and gaming, the other in software development.

WineHQ was able to ship a new version of Mono, 6.14.0 on Mar 8, 2025, and its release notes contains more than just the technical details, but also a lot of historical context introduced by Esme Povirk, the mastermind behind this ownership change. The Mono Project is not dead, but rather has entered a new phase of life under the stewardship of WineHQ. The future may hold exciting developments for both Mono and the broader .NET ecosystem.