Chipworkx to g400 migration

I have the source code for a application that ran on chipworkx.
I realize there is no longer a nand and I will deal with that.
I realize that SD is changed and can deal with that.
I also realize that I have to update the pin assignments as they have changed.
What I wonder is this:
On Chipworkx we used these GHI references:
GHIElectronics.NetMF.Hardware
GHIElectronics.NetMF.Hardware.Chipworkx
GHIElectronics.NetMF.IO
GHIElectronics.NetMF.System
GHIElectronics.NetMF.USBHost
What replaces them?

Also
Should I change my target framework to 4.3? or leave it on 4.1?

Ok and what references do I use to replace the old GHI references?
I ask because I cant find a reference for the g400. is it needed?

It depends on what features tour are using. The documentation include the reference needed for each feature. https://www.ghielectronics.com/docs?tags=netmf