Article 30 of the Trademark Law of People's Republic of China (PRC) stipulates: "Where a registered trademark is used in one of the following acts, the Trademark Office shall order it to correct or revoke its registered trademark within a time limit:

(1) changing the words, graphics or their combination of a registered trademark by itself;

(2) Changing the name, address or other registered items of the registrant of a registered trademark;

(3) Transferring a registered trademark by itself;

(4) Stop using it for three consecutive years. "

Please pay attention to the third item. So, it's not just a matter of not having an official seal.