If I no longer own the vehicle a license renewal sticker is soon due , do I just ignore it and let it expire? I sold the vehicle to a private party and signed the title over to him. The new vehicle I bought required a different plate class.

Correct. The new owner has not registered the vehicle yet or did it after the renewal notice was sent.

What allen said......

I'm not an expert, but I believe you are correct, just ignore it. But I'm sure if you call them, they can confirm. It also might mean they don't have a record of you selling it.