Migrating from Previous Releases of Uno Platform

This article details the migration steps required to migrate from one version to the next when breaking changes are being introduced.

Uno Platform 4.10

This release does not require upgrade steps.

Uno Platform 4.9

This release does not require upgrade steps.

Uno Platform 4.8

This release does not require upgrade steps.

Uno Platform 4.7

Symbol Fonts

Uno Platform 4.7 now brings the Uno Fluent Symbols font implicitly. You can remove:

  • The uno-fluentui-assets.ttf file from all your project heads,
  • Any reference to uno-fluentui-assets.ttf in the UIAppFonts sections of the iOS Info.plist

Breaking change with ms-appx:/// resolution

Uno Platform 4.7 brings a behavior breaking change where the library Assets feature introduced in Uno Platform 4.6 required assembly names to be lower cased.

If you had an asset in a nuget package or project named "MyProject", you previously had to write ms-appx:///myproject/MyAsset.txt. With 4.7, you'll need to write ms-appx:///MyProject/MyAsset.txt.

Uno Platform 4.6

Breaking change with Android 13

The introduction of Android 13 lead to a breaking change, as some Android members exposed to .NET where removed.

You'll need to migrate from BaseActivity.PrepareOptionsPanel to BaseActivity.PreparePanel instead.

Uno Platform 4.5


The built-in ElevatedView control has undergone a visual unification, which means existing apps may experience slightly different shadow visuals, especially on Android, which now supports the full range of colors including opacity. If you encounter visual discrepancies, please tweak the Elevation and ShadowColor properties to fit your needs.

Uno Platform 4.1

Android 12 support

Uno 4.1 removes the support for the Android SDK 10 and adds support for Android 12. Note that Android 10 versions and below are still supported at runtime, but you'll need to have Android 11 SDK or later to build an Uno Platform App. You can upgrade to Android 11 or 12 using the Compile using Android version: (Targer Framework) option in Visual Studio Android project properties.

Additionally, here are some specific hints about the migration to Android 12:

  • If you are building with Android 12 on Azure Devops Hosted Agents (macOS or Windows), you'll need two updates:
    • Use the JDK 11, using the following step:
      - pwsh: |
          echo "##vso[task.setvariable variable=JAVA_HOME]$(JAVA_HOME_11_X64)"
          echo "##vso[task.setvariable variable=JavaSdkDirectory]$(JAVA_HOME_11_X64)"
      displayName: Select JDK 11
    • You may need to add the following property to your android csproj:
  • The AndroidX libraries need to be at specific versions to avoid an upstream android issue. The Uno Platform NuGet packages are using those versions automatically, but if you override those packages, make sure to avoid direct or indirect dependencies on Xamarin.AndroidX.Core(>= For reference, view this page to get the packages versions used by Uno Platform.

Uno Platform 4.0

Uno 4.0 introduces a set of binary and source breaking changes required to align with the Windows App SDK 1.0.

To migrate your application to Uno 4.0:

  • Update all Uno.UI.* nuget packages to 4.0
  • Add a package reference to Uno.UI.Adapter.Microsoft.Extensions.Logging to all your project heads (Except .Desktop for WinUI projects, and .Windows for UWP projects)
  • In your ConfigureLogging method, add the following block at the end:
    #if HAS_UNO
  • If you are using ApiInformation.NotImplementedLogLevel, use the following code instead:
    global::Uno.UI.FeatureConfiguration.ApiInformation.NotImplementedLogLevel = global::Uno.Foundation.Logging.LogLevel.Debug; // Raise not implemented usages as Debug messages
  • Many other smaller breaking changes that may have previously forced #if HAS_UNO conditionals, such as:
    • FrameworkElement.DataContextChanged signature
    • FrameworkElement.Loading signature
    • Popup is now correctly in the Primitives namespace
    • FlyoutBase event signatures
  • Uno.UI packages no longer depend on Uno.Core. If you did depend on types or extensions provided by this package, you can take a direct dependency on it, or use one of the sub packages created to limit the number of transitive dependencies.
  • The Uno.UI.DualScreen package is now renamed as Uno.UI.Foldable

Uno Platform 3.6

Optional upgrade for Microsoft.Extension.Logging

Uno Platform 3.6 templates provide an updated version of the loggers to allow the use of updated Microsoft.Extension.Logging.* logging packages. It is not required for applications to upgrade to these newer loggers, yet those provide additional features particularly for iOS and WebAssembly.

Here's how to upgrade:

  • For all projects:
    • Remove references to the Microsoft.Extensions.Logging.Filter package
    • Add a reference to the Microsoft.Extensions.Logging package version 5.0.0
    • Upgrade the Microsoft.Extensions.Logging.Console package to version 5.0.0
  • For UWP:
    • Change the reference from Microsoft.Extensions.Logging.Console to Microsoft.Extensions.Logging.Debug
  • For WebAssembly:
    • Add the following line to the LinkerConfig.xaml file:
      <assembly fullname="Microsoft.Extensions.Options" />
    • Add a reference to Uno.Extensions.Logging.WebAssembly.Console version 1.0.1
  • For iOS:
    • Add a reference to Uno.Extensions.Logging.OSLog version 1.0.1
  • In the App.xaml.cs file:
    • Replace the ConfigureFilters() method with the following:
                /// <summary>
                /// Configures global Uno Platform logging
                /// </summary>
                private static void InitializeLogging()
                    var factory = LoggerFactory.Create(builder =>
        #if __WASM__
                        builder.AddProvider(new global::Uno.Extensions.Logging.WebAssembly.WebAssemblyConsoleLoggerProvider());
        #elif __IOS__
                        builder.AddProvider(new global::Uno.Extensions.Logging.OSLogLoggerProvider());
        #elif NETFX_CORE
                        // Exclude logs below this level
                        // Default filters for Uno Platform namespaces
                        builder.AddFilter("Uno", LogLevel.Warning);
                        builder.AddFilter("Windows", LogLevel.Warning);
                        builder.AddFilter("Microsoft", LogLevel.Warning);
                        // Generic Xaml events
                        // builder.AddFilter("Windows.UI.Xaml", LogLevel.Debug );
                        // builder.AddFilter("Windows.UI.Xaml.VisualStateGroup", LogLevel.Debug );
                        // builder.AddFilter("Windows.UI.Xaml.StateTriggerBase", LogLevel.Debug );
                        // builder.AddFilter("Windows.UI.Xaml.UIElement", LogLevel.Debug );
                        // builder.AddFilter("Windows.UI.Xaml.FrameworkElement", LogLevel.Trace );
                        // Layouter specific messages
                        // builder.AddFilter("Windows.UI.Xaml.Controls", LogLevel.Debug );
                        // builder.AddFilter("Windows.UI.Xaml.Controls.Layouter", LogLevel.Debug );
                        // builder.AddFilter("Windows.UI.Xaml.Controls.Panel", LogLevel.Debug );
                        // builder.AddFilter("Windows.Storage", LogLevel.Debug );
                        // Binding related messages
                        // builder.AddFilter("Windows.UI.Xaml.Data", LogLevel.Debug );
                        // builder.AddFilter("Windows.UI.Xaml.Data", LogLevel.Debug );
                        // Binder memory references tracking
                        // builder.AddFilter("Uno.UI.DataBinding.BinderReferenceHolder", LogLevel.Debug );
                        // RemoteControl and HotReload related
                        // builder.AddFilter("Uno.UI.RemoteControl", LogLevel.Information);
                        // Debug JS interop
                        // builder.AddFilter("Uno.Foundation.WebAssemblyRuntime", LogLevel.Debug );
                    global::Uno.Extensions.LogExtensionPoint.AmbientLoggerFactory = factory;
    • In the constructor, remove this call:
      and replace it with:

Note that there are two new loggers:

  • Uno.Extensions.Logging.OSLog which provides the ability to log the the iOS system logs
  • Uno.Extensions.Logging.WebAssembly.Console which provides thread safe and colored logging to the browser debugger console

Migrating WebAssembly projects to .NET 5

If your WebAssembly project is using the netstandard2.0 TargetFramework, migrating to net5.0 can be done as follows:

  • Change <TargetFramework>netstandard2.0</TargetFramework> to <TargetFramework>net5.0</TargetFramework>
  • Upgrade Uno.Wasm.Bootstrap and Uno.Wasm.Bootstrap.DevServer to 2.0.0 or later
  • Add a reference to the Microsoft.Windows.Compatibility package to 5.0.1

You may also want to apply the changes from the section above (logger updates) to benefits from the update to .NET 5.

Uno Platform 2.x to Uno 3.0

Migrating from Uno 2.x to Uno 3.0 requires a small set of changes in the code and configuration.

  • Android 8.0 is not supported anymore, you'll need to update to Android 9.0 or 10.0.
  • For Android, you'll need to update the Main.cs file from:
      : base(new App(), javaReference, transfer)
      : base(() => new App(), javaReference, transfer)
  • For WebAssembly, in the YourProject.Wasm.csproj:
    • Change <PackageReference Include="Uno.UI" Version="2.4.4" /> to <PackageReference Include="Uno.UI.WebAssembly" Version="3.0.12" />
    • Remove <WasmHead>true</WasmHead>
    • You can remove __WASM__ in DefineConstants
  • The symbols font has been updated, and the name needs to be updated. For more information, see this article.