If you’re still using the older version of Application Insights in the Visual Studio Online portal, you’ll have to update your application to use the new version hosted in the Azure Preview portal by October 15.
We announced in an August blog post on Azure Blogs that Application Insights has transitioned from the Visual Studio Online portal to being one of the services offered in the new Azure Preview portal.

In the last year, Application Insights has been making a transition from being part of the Visual Studio Online Portal to be one of the services offered in the new Azure Preview portal. It has been our vision to provide you complete 360°

You can currently use Application Insights to find out how people use your Windows 8.1 Store Apps & Managed Windows Phone 8.0 Apps. We’ve been asked about Phone 8.0 Direct3D C++ Apps as well, which the NuGet Package currently does not support.