Xamarin.Android Deployment Error

Question

I am working with Xamarin.Android in visual studio 2015 , while building the solution i am not getting any error or warning but while deploying iam getting the following Warning.

Please help me solve  this issue.

 

The $(TargetFrameworkVersion) for Registration.dll (v7.0) is greater than the $(TargetFrameworkVersion) for your project (v6.0). You need to increase the $(TargetFrameworkVersion) for your project.