Created Unassigned: Extended WPF Toolkit not supported in Universal App [22180]

In Visual Studio 2015, creating a new Blank App (Universal Windows) targeting .NET Framework 4.5.2 and attempting to add Extended WPF Toolkit Community Edition 2.6.0 via NuGet results in the following error and the package reference not being added to the project:

Restoring packages for C:\<PathToProject>\project.json...
Extended.Wpf.Toolkit 2.6.0 is not compatible with UAP,Version=v10.0.
Some packages are not compatible with UAP,Version=v10.0.
Extended.Wpf.Toolkit 2.6.0 is not compatible with UAP,Version=v10.0 (win10-arm).
Some packages are not compatible with UAP,Version=v10.0 (win10-arm).
Extended.Wpf.Toolkit 2.6.0 is not compatible with UAP,Version=v10.0 (win10-arm-aot).
Some packages are not compatible with UAP,Version=v10.0 (win10-arm-aot).
Extended.Wpf.Toolkit 2.6.0 is not compatible with UAP,Version=v10.0 (win10-x86).
Some packages are not compatible with UAP,Version=v10.0 (win10-x86).
Extended.Wpf.Toolkit 2.6.0 is not compatible with UAP,Version=v10.0 (win10-x86-aot).
Some packages are not compatible with UAP,Version=v10.0 (win10-x86-aot).
Extended.Wpf.Toolkit 2.6.0 is not compatible with UAP,Version=v10.0 (win10-x64).
Some packages are not compatible with UAP,Version=v10.0 (win10-x64).
Extended.Wpf.Toolkit 2.6.0 is not compatible with UAP,Version=v10.0 (win10-x64-aot).
Some packages are not compatible with UAP,Version=v10.0 (win10-x64-aot).
Package restore failed for '<ProjectName>'.