Wrong License purchased

I've been developing in Vision. "They" bought Perspective. Oops. Do I just have to suck it up and start over? What functionality will be lost, if any?

This sounds like a good question for your sales rep. Perspective is a significantly different technology, so you would be starting over from scratch.

Here is a recent conversation that discusses the functional differences between Perspective and Vision:

Depends on what your project is doing. I find Perspective much faster and easier to deploy, but still have projects running in both for specific reasons.

That would be a question for you sale rep. They may be able to switch it and discuss any related pricing issues. Or they might say they can't switch it. In which case you re develop.

But worth asking the sales rep for sure. Unless client wants in perspective.