My patent expired some years back. I was not knowledgeable as to how to market it back then. Could I create a new version of it and patent that? I know I could easily market it, as is, on Youtube now. It is very easy to rip off though. I had paid its maintenance dues through the years, and it expired because of the 17 year life of the patent protection.
You can patent a new and improved version of your original patent if the novel claims are not obvious from your prior patent and the other prior art.
But please note that the original invention -- the one that your expired patent covered -- is now in the public domain, and you no longer have the right to stop others from making, selling, or using anything that was covered by that disclosure. As Kevin stated, a new and improved version may still be patent eligible.– user4545Jul 4, 2014 at 14:21