This situation is very common. There is no substantive examination for utility models. Anyone can apply if they make slight improvements based on others. In case of a lawsuit, let the Patent Office conduct a substantive examination of the previously applied utility model to see whether it has been published abroad, whether it has been applied for domestically, and whether it has practicality, novelty, and creativity. If so, the patent applied for later can be invalidated and considered an infringement. If it does not possess the three characteristics, the utility model applied for first will be invalid, and the utility model applied later will not be considered an infringement. If the invention has high value, it is the first in the country, or it is a breakthrough product, then you can apply for invention and the invention protection period will be twenty years.