Microsoft.Data.Services.Client assembly missing after upgrade to 6.1 and .Net 4.5.1

On the IaaS server (Designer) I was using the following bit of code to get the machine object (I need this to set the vmname passed back from orchestrator):

machine = mgmtContext.VirtualMachines.Where(Function (vm ) vm.VirtualMachineID = virtualmachineid).FirstOrDefault()

After the upgrade I'm getting the following missing assembly error:

Is Warning: Message False"Compiler error(s) encountered processing expression ""mgmtContext.VirtualMachines.Where(Function (vm ) vm.VirtualMachineID = virtualmachineid).FirstOrDefault()"".

Reference required to assembly 'Microsoft.Data.Services.Client, Version=5.6.1.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' containing the base class 'System.Data.Services.Client.DataServiceContext'. Add one to your project.

"

I'm assuming that this assembly is not included in .net 4.5.1 - but I'm unsure. 

Does anyone know a fix?  Or a better way to set the name of the machine?

Thanks!