After a utility model patent expires, others change it before applying. Is it infringement to produce products similar to the original patent?

Producing products with the same nature as the products is not infringement, because A's patented technology is already open technology, and anyone can produce products or products with the same nature. As for the B patent, whether it is a little modification or a lot of modification, the key is to analyze whether these modifications have produced technical effects. If yes, it is suggested not to produce product B, which will infringe upon the rights. If not, even if it is simply replaced on the basis of patent A, or replaced by the usual means in the industry, it is not infringing.