A programmer on your team is great at maintaining the old legacy system. But the company has switched to a new technology/platform.
What do you do with the no-longer-effective developer?
Try to smoothly move him to the new technology/platform - first give him small assignments, then bigger ones, then move him completely.
If he's a good programmer he will learn and adapt, if not, explain to him that he will have to think of another position - either in the same company or in another one. It's business, not his playground.