Windows Phone Toolkit cannot install with WP8.0

Successfully installed ‘WPtoolkit 4.2013.08.16’. Successfully uninstalled ‘WPtoolkit 4.2013.08.16’. Install failed. Rolling back… Could not install package ‘WPtoolkit 4.2013.08.16’. You are trying to install this package into a project that targets ‘WindowsPhone,Version=v8.0’, but the package does not contain any assembly references that are compatible with that framework. For more information, contact the package author. When I met the issue, it means I could not install the nuget package. The way to solve the issue is go to http://www.nuget.org and install the latest package.