The namespace 'Notifications' does not exists in the namespace Microsoft.ServiceBus

I was getting started to make use of the notification hubs and got stumbled in the first step itself.  I am creating a console application to push out notifications. 

I added ServiceBus reference using the package manger console.

Install-PackageWindowsAzure.ServiceBus

I added the reference 

1. usingMicrosoft.ServiceBus.Notifications;

 Then i end up with the error "The namespace 'Notifications' does not exists in the namespace Microsoft.ServiceBus". 

 I am unable to decipher what is the issue here. I am using .net  framework 4.5