Migrate to Fabulous 10.0.x

Fabulous 10 unifies core, MAUI, Avalonia, extensions, templates, samples, and releases in this repository. The NuGet package ID for core remains Fabulous, and public namespaces remain Fabulous; the project and assembly are named Fabulous.Core. All maintained packages now share the 10.0.x release line.

From Fabulous 3 prereleases

  1. Remove prerelease pins such as 3.0.0-pre22 or 3.0.0-pre23 and reference the same 10.0.x version for Fabulous, Fabulous.MauiControls or Fabulous.Avalonia, and any maintained extensions.
  2. Replace references to the former platform repositories with package references or the new source locations under src/maui and src/avalonia.
  3. Reinstall Fabulous.MauiControls.Templates or Fabulous.Avalonia.Templates at 10.0.x, generate a temporary app, and compare project hosts/resources with your app.
  4. Build every target and run update tests plus backend UI tests. Do not infer device compatibility from a neutral build.

Most Fabulous 3 MVU code keeps Program.stateful, statefulWithCmd, or statefulWithCmdMsg; verify tuple shapes against programs and commands. Use the current MAUI and Avalonia samples when an imported prerelease example differs.

From Fabulous 2 or Xamarin.Forms

There is no maintained Xamarin.Forms backend in Fabulous 10. Migrate the host to .NET MAUI or Avalonia and replace Fabulous.XamarinForms imports, XamarinFormsProgram.run, and Xamarin.Forms control types with the chosen backend. Do not mechanically rename namespaces: create a current template app, move the model/update logic first, then rebuild the view using current builders and modifiers.

Replace old View.* constructors with the backend's current open type Fabulous.Maui.View or open type Fabulous.Avalonia.View style. Revisit navigation, styles, platform services, permissions, and ViewRef code because their native APIs changed. The two end-to-end tutorials and UI guide provide current starting points.

Finish by removing retired packages and links, clearing bin/obj, restoring, and checking the installed package graph:

dotnet list package --include-transitive
dotnet build -c Release
dotnet test -c Release