Upgrade MAUI to .NET 9.0

Intro

I want to explain how to upgrade my Blog_MAUI_ComponentLibrary project from .NET 8.0 to 9.0. I recommend Microsoft’s great article about what’s new in .NET 9.0. It includes a section called Upgrade from .NET 8 to .NET 9.

Upgrade to .NET 9.0

NET 9.0 was released on 12/11/2024. It includes new controls and better performance for .NET MAUI. Let’s begin the upgrade journey! 🚀

Update your IDE

The first step I recommend is updating your IDE. I use Rider, so I updated it to the latest version. If you use Visual Studio, make sure to update it too.

On rider, I am using the Build #RD-243.21565.191, built on November 13, 2024.

Rider Version

Install .NET 9

First of all, I need to install .NET 9.0 from Microsoft.

Update Android SDK Manager and XCode

My project Blog_MAUI_ComponentLibrary target Android and iOS platform.

I installed Android 35 from Android SDK Manager.

Android SDK Manager Version

I updated Xcode to the latest version as well.

XCode Version

Update dotnet maui workload

The .NET MAUI workload is a set of tools and libraries required to build cross-platform apps using .NET MAUI (Multi-platform App UI). It allows you to create applications for Android, iOS, macOS, and Windows from a single codebase.

I already have the .NET MAUI workload installed. To restore workloads, run these commands:

dotnet workload restore
dotnet restore

If you don’t have the MAUI workload installed, use:

dotnet workload install maui

Here my workload:

dotnet workload maui version

Update .csproj

In the .csproj file, you will find a reference to TargetFramework set to net8.0. Update it to net9.0 to target the latest framework.

<Project Sdk="Microsoft.NET.Sdk">

    <PropertyGroup>
        <TargetFrameworks>net9.0-android;net9.0-ios;net9.0-maccatalyst</TargetFrameworks>
        <TargetFrameworks Condition="$([MSBuild]::IsOSPlatform('windows'))">
            $(TargetFrameworks);net9.0-windows10.0.19041.0
        </TargetFrameworks>
        ...
    </PropertyGroup>
</Project>

If your app targets iOS or Mac Catalyst, update the $(SupportedOSPlatformVersion) build properties for these platforms to 15.0:

<SupportedOSPlatformVersion 
Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'ios'">
    15.0</SupportedOSPlatformVersion>

<SupportedOSPlatformVersion 
Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'maccatalyst'">
    15.0</SupportedOSPlatformVersion>

Update all csproj to net9.0

Remember to upgrade all your projects to .NET 9.0.

Upgrade all projects to .NET 9.0

Update Microsoft.Maui packages

It’s important to update all Microsoft.Maui.Controls.* to 9.X.X.

In my case I updated all packages to the latest version:

Community Toolkit.Maui,
Microsoft.Extensions.Dependencyinjection.Abstractions
Microsoft.Extensions.Logging.Debug
Microsoft.Maui.Controls
Microsoft.Maui.Controls.Compatibility
Microsoft.Maui.Controls.Core
SkiaSharp.Views.Maui.Controls
SkiaSharp.Views.Maui.Core

Blog_MAUI_ComponentLibrary packages

Build and read new warning

Let’s run a dotnet build command and see the output:

dotnet clean
dotnet build

Build with new warning

We notice we do have many warning, on my project I have 11 new warning.

By default, .NET MAUI 9 produces build warnings for bindings that don’t use compiled bindings. For more information about XAML compiled bindings warnings, see XAML compiled bindings warnings.

Pay attention to newly deprecated APIs, as they will be completely removed in a future release. Warnings include the Frame control, the MainPage object, compatibility layout classes in the Microsoft.Maui.Controls.Compatibility namespace, and legacy measure calls.

Note: the XAML compiler error codes have changed their prefix from XFC to XC, describe here.

Conclusion

The full code is available on GitHub, with a working example.

Upgrading your .NET MAUI application to .NET 9.0 unlocks powerful new features and performance improvements, but it also comes with changes that can introduce technical debt if not addressed promptly.

It is crucial to carefully review and resolve all build warnings, as these often highlight deprecated APIs, obsolete features, or potential issues with compatibility. Ignoring these warnings may lead to larger challenges in future updates as APIs are removed or behaviors change.

By tackling warnings now, you not only ensure a smoother upgrade path for future versions of .NET but also maintain a clean and maintainable codebase. This proactive approach reduces technical debt, improves project stability, and allows your team to focus on building new features rather than firefighting issues.

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Happy coding!