There is no clear requirement, but GEM requires listed companies to have innovation ability, mainly product and technology innovation, if they are manufacturing enterprises. Invention patents unrelated to the main business may be considered as weak in innovation ability. In addition, many GEM companies are high-tech enterprises, which need independent intellectual property rights of core technologies. Without patents, they may be considered as not meeting the requirements of high-tech enterprises, and there is the possibility of paying taxes. If you only have utility model patents, it proves that your core technology may not be so innovative and advanced.
Of course, it's hard to say which company can't go public just because it lacks an invention patent. It can only be said that the invention patent is still relatively important, and the case can be seen in Gaode Infrared.