I bit confused by the literature, can a minnkota trolling motor with ipilot be upgraded to ipilotlink in order to communicate with hummingbird graphs?
Particular unit in question is a 2016 riptide.
If so what parts are required?

Yes it can for a nominal fee.

https://www.trollingmotors.net/products/i-pilot-link-for-riptide-st

It is a simple upgrade if you are willing to pay the price. You get the top half of the head of the TM and a different remote (old remote will also still work). You remove the screws under the head of the TM, when you separate the two halves, pay attention to how the wires were routed inside. Unplug wires, 3 of them if memory serves me right, plug the new head in and screw it back together. You might find it better to sell your older one and just buy a new one with it already installed and get the better performing spotlock. You also might look around for someone who has the link on an older unit that doesn't use it and pay them to swap out the heads.

I just upgraded my Ulterra from I pilot to I pilot link. It cost me $800. I got the head with ethernet cable, an antenna, and a remote. I don't know about your I pilot old remotes but mine won't work with the link.

Thanks for the info guys. Probably will follow thru with the upgrade, I want to be able to follow map contour lines and on my particular unit the spotlock performance was a major disappointment anyway.

Interesting that the I pilot link is not apparently available as an option on the new terrova motors, but if buy the upgrade kit you will end up at the ulterra price.