--- title: .NET 11 Preview 6: CoreCLR replaces Mono for MAUI, plus... description: .NET 11 Preview 6 is now available with CoreCLR fully replacing Mono as the runtime for .NET MAUI mobile apps. iOS and Mac Catalyst apps are generally faster,... canonical: https://daily.dev/posts/net-11-preview-6-coreclr-replaces-mono-for-maui-plus-runtime-and-ecosystem-updates-wzk7gt5ar twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: .NET 11 Preview 6: CoreCLR replaces Mono for MAUI, plus runtime and ecosystem updates | daily.dev og:description: .NET 11 Preview 6 is now available with CoreCLR fully replacing Mono as the runtime for .NET MAUI mobile apps. iOS and Mac Catalyst apps are generally faster,... og:url: https://daily.dev/posts/net-11-preview-6-coreclr-replaces-mono-for-maui-plus-runtime-and-ecosystem-updates-wzk7gt5ar og:image: https://api.daily.dev/og/posts/WZk7Gt5aR.png og:image:alt: .NET 11 Preview 6: CoreCLR replaces Mono for MAUI, plus runtime and ecosystem updates og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # .NET 11 Preview 6: CoreCLR replaces Mono for MAUI, plus runtime and ecosystem updates **[Collections](https://daily.dev/sources/collections)** · 3 min read · 8 upvotes · 0 comments ## Summary .NET 11 Preview 6 is now available with CoreCLR fully replacing Mono as the runtime for .NET MAUI mobile apps. iOS and Mac Catalyst apps are generally faster, Android is within ~10% of Mono on startup and size, and full .NET diagnostics tooling (dotnet-trace, dotnet-counters) now works on mobile. NativeAOT foundations for Android are also included. MAUI gains pin clustering for Maps, CancellationToken support for animations, a new LongPressGestureRecognizer, Material 3 defaults for Android controls, and automatic CSS stripping for unused stylesheets. ASP.NET Core adds automatic CSRF protection and OpenAPI 3.2 as default. EF Core gets LINQ translation improvements and unconstrained foreign key support. Blazor Virtualize adds scroll-to-item, SignalR gets authentication refresh, and dotnet test now supports xUnit v3. The GA release is targeted for November. ## Content ## Overview .NET 11 Preview 6 is out, and it's a substantial release. Changes span the runtime, ASP.NET Core, the Base Class Library, .NET MAUI, and tooling. Here's a rundown of what's actually in it. --- ## Runtime and performance The JIT has been improved again, and NativeAOT gets faster interface dispatch. Runtime-async support lands as a performance improvement for async code paths, and SIMD lane construction APIs are new for low-level numeric work. Memory management is better across the board, and the diagnostics story has expanded: `dotnet-trace` and `dotnet-counters` now work on mobile devices, not just desktop. --- ## CoreCLR replaces Mono for .NET MAUI This is the big one for mobile developers. Starting with Preview 6, CoreCLR is the sole runtime for .NET MAUI on iOS, Mac Catalyst, and Android. Mono is gone. In practice: - iOS and Mac Catalyst apps are generally faster than they were on Mono - Android startup time and app size are within about 10% of Mono - close, but not quite there yet - Debugging and Hot Reload work in both Visual Studio and VS Code, with some rough edges still being smoothed out - NativeAOT foundations for Android are landing alongside this The team is asking developers to test their apps against Preview 6 now and report back on performance benchmarks, package sizes, and any regressions before the GA release in November. --- ## ASP.NET Core **Async validation in Minimal APIs** is probably the most developer-facing addition here. There are two new mechanisms: - `AsyncValidationAttribute` - a custom data annotation attribute with an `IsValidAsync` method that can resolve DI services via `ValidationContext` - `IAsyncValidatableObject` - object-level async validation that returns `IAsyncEnumerable` Both require their synchronous counterparts to be present (since they extend existing interfaces), but those synchronous methods just throw - the framework always calls the async path when using `Microsoft.Extensions.Validation`. Other ASP.NET Core changes: - Automatic CSRF protection is now built in - OpenAPI 3.2 is the default - Request handling is faster, routing is improved - SignalR gets authentication refresh support - Blazor's `Virtualize` component gains scroll-to-item --- ## Base Class Library - Stream adapters for memory and text - `System.Text.Json` now supports C# union types - LINQ gets more query translation improvements - Networking improvements --- ## EF Core - More LINQ query translation improvements - Unconstrained foreign key relationships are now supported --- ## .NET MAUI Beyond the CoreCLR switch, there are several quality-of-life additions: **Maps** - Automatic pin clustering for dense locations, custom marker images via `ImageSource`, and Google Maps JSON style support. **Animations** - `CancellationToken` support on animation methods, so you can stop individual animations without canceling everything. The non-async versions (`FadeTo()`, `RotateTo()`, etc.) are now marked obsolete. **Gestures** - A new `LongPressGestureRecognizer` makes long-press detection straightforward. **BoxView** - Gains a `Fill` property that supports gradients. **App size** - Apps that don't use CSS stylesheets will have that infrastructure stripped at publish time automatically. **Android** - Several controls now default to Material 3 styling. **Windows** - `CollectionView2` lands for Windows. --- ## Tooling `dotnet test` gets expanded options with xUnit v3 and NUnit support. --- ## F# Several language improvements are included, though the specifics are still being documented. --- ## Should you upgrade now? Preview 6 is for testing and exploration, not production. If you're a .NET MAUI developer especially, now is the right time to run your app against it - the CoreCLR migration is a significant change and the team needs real-world feedback before November's GA release. ## Questions this post answers ### Does .NET MAUI still use Mono for iOS and Android in .NET 11? No, starting with .NET 11 Preview 6, CoreCLR is the sole runtime for .NET MAUI on iOS, Mac Catalyst, and Android, replacing Mono entirely. iOS and Mac Catalyst apps are generally faster under CoreCLR, while Android startup time and app size are within about 10% of what Mono delivered. NativeAOT foundations for Android are also landing alongside this change. _Teams planning a MAUI upgrade can track runtime migration details like this on daily.dev before GA ships in November._ ### How do I add async validation to a Minimal API in ASP.NET Core? ASP.NET Core in .NET 11 introduces AsyncValidationAttribute, a custom data annotation with an IsValidAsync method that can resolve DI services via ValidationContext, and IAsyncValidatableObject for object-level async validation returning IAsyncEnumerable. Both require synchronous counterparts to be present, but those synchronous methods simply throw since the framework always calls the async path via Microsoft.Extensions.Validation. _Developers adopting async validation patterns in Minimal APIs can follow ASP.NET Core changes like this on daily.dev._ ### Are the non-async animation methods like FadeTo and RotateTo deprecated in .NET MAUI? Yes, in .NET 11 the non-async animation methods such as FadeTo() and RotateTo() are now marked obsolete, in favor of versions that support CancellationToken so individual animations can be stopped without canceling everything else running. _MAUI developers updating animation code can track obsolete API changes like this on daily.dev before migrating._ ## Similar posts on daily.dev - [Microsoft Releases .NET 11 Preview 6 With Language and Framework Updates](https://daily.dev/posts/microsoft-releases-net-11-preview-6-with-language-and-framework-updates-oqwjdzv3l) · InfoQ · 6 upvotes · 0 comments - [Microsoft Releases .NET 11 Preview 3 with Updates Across Runtime, SDK, MAUI, and ASP.NET Core](https://daily.dev/posts/microsoft-releases-net-11-preview-3-with-updates-across-runtime-sdk-maui-and-asp-net-core-4tyjhbtqm) · InfoQ · 5 upvotes · 1 comments --- Tags: [#.net](https://daily.dev/tags/.net), [#aspnet](https://daily.dev/tags/aspnet), [#.net-maui](https://daily.dev/tags/.net-maui) [View this post on daily.dev](https://daily.dev/posts/net-11-preview-6-coreclr-replaces-mono-for-maui-plus-runtime-and-ecosystem-updates-wzk7gt5ar) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":".NET 11 Preview 6: CoreCLR replaces Mono for MAUI, plus runtime and ecosystem updates","url":"https://daily.dev/posts/net-11-preview-6-coreclr-replaces-mono-for-maui-plus-runtime-and-ecosystem-updates-wzk7gt5ar","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/net-11-preview-6-coreclr-replaces-mono-for-maui-plus-runtime-and-ecosystem-updates-wzk7gt5ar"},"datePublished":"2026-07-14T18:43:31.705Z","dateModified":"2026-09-13T19:36:11.598Z","description":".NET 11 Preview 6 is now available with CoreCLR fully replacing Mono as the runtime for .NET MAUI mobile apps. iOS and Mac Catalyst apps are generally faster,...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/7bd73545a81763293f7afe378936e497?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/7bd73545a81763293f7afe378936e497?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Collections","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Collections","logo":"https://media.daily.dev/image/upload/s--fk_6ycEi--/f_auto,q_auto/v1780996001/logos/collections?_a=BAMAMiWQ0","url":"https://daily.dev/sources/collections"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/net-11-preview-6-coreclr-replaces-mono-for-maui-plus-runtime-and-ecosystem-updates-wzk7gt5ar","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":8},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":".net,aspnet,.net-maui","timeRequired":"PT3M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Collections","item":"https://daily.dev/sources/collections"},{"@type":"ListItem","position":3,"name":".NET 11 Preview 6: CoreCLR replaces Mono for MAUI, plus runtime and ecosystem updates"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/net-11-preview-6-coreclr-replaces-mono-for-maui-plus-runtime-and-ecosystem-updates-wzk7gt5ar#faq","mainEntity":[{"@type":"Question","name":"Does .NET MAUI still use Mono for iOS and Android in .NET 11?","acceptedAnswer":{"@type":"Answer","text":"No, starting with .NET 11 Preview 6, CoreCLR is the sole runtime for .NET MAUI on iOS, Mac Catalyst, and Android, replacing Mono entirely. iOS and Mac Catalyst apps are generally faster under CoreCLR, while Android startup time and app size are within about 10% of what Mono delivered. 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