Caliburn.Micro Xaml made easy

Migrating to 4.0.0

Supported Platforms

One of the guiding philosophies we’ve had about supported platforms for Caliburn.Micro is to support the platforms that are supported by the latest version of Visual Studio.

Given this we’ve dropped support for the following platforms.

  • Silverlight 5
  • Windows Phone 8 (Silverlight)
  • Windows Phone 8 (Windows Runtime)
  • Windows 8.1

We’ll also be discontinuing support for .NET 4.0 for WPF. The minimum version of .NET for WPF is now 4.5.

All of these platforms are still supported in the 3.x releases.


Below is the changes included in 4.0.0 release (so far).


The platforms targeted have been changed to support the new .NET ecosystem. These include:

  • Caliburn.Micro.Core targets .NET Standard 1.0.
  • Caliburn.Micro.Platform.Xamarin.Forms targets .NET Standard 1.4.
  • Caliburn.Micro.Platform is consistently named across all platforms (previously UWP included the platform name).

Event Aggregator

The Event Aggregator is the first class to go through major breaking changes, this brings it into an async implementation approach that is the main reason for 4.0.0.

The full changes are available in the event aggregator migration documentation.

Screens and view model lifecyle

All the interfaces that support view model lifecycle such as IActivate and IGuardClose now support an async implementation.

The full changes are available in the Screen migration documentation.