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Microsoft's implementation of ASP.NET is not part of the standardized CLI, and while Microsoft's runtime environment and development tools are not subject to comparable secrecy agreements to Java EE, the official Microsoft tools are not open source or free software, and require Windows servers. However, a cross-platform free software ASP.NET implementation is part of the Mono project (minus webparts and Web Services Enhancements).[20] Mono supports ASP.NET 4.0 including Web Forms, Microsoft AJAX, and ASP.NET MVC.[21] While Mono supports ASP.NET MVC 3 applications, only MVC 2 is installed by default because the Razor view engine is not available as Open Source.[22]