Visual Studio 2017 - What happened to Expression interactions?

A little update as for 2020:

As mentioned by Jan in other question:

Microsoft open-sourced XAML Behaviours and posted a blog post how to update to this version.

Steps to proceed with update:

1. Remove reference to “Microsoft.Expression.Interactions” and “System.Windows.Interactivity”.
2. Install the Microsoft.Xaml.Behaviors.Wpf NuGet package.
3. XAML files – replace the xmlns namespaces http://schemas.microsoft.com/expression/2010/interactivity and http://schemas.microsoft.com/expression/2010/interactions with http://schemas.microsoft.com/xaml/behaviors
4. C# files – replace the usings in c# files “Microsoft.Xaml.Interactivity” and “Microsoft.Xaml.Interactions” with “Microsoft.Xaml.Behaviors”

Use the Visual Studio 2017 installer to install "Blend for Visual Studio SDK for .NET", which you can find on the "Individual components" page, under the "SDKs, libraries, and frameworks" heading.