legal ground
Article 14 of the Measures for Filing Patent Licensing Contracts
The relevant contents of the patent licensing contract shall be registered in the patent register by China National Intellectual Property Administration, and the following contents shall be announced in the patent gazette: licensor, licensee, main classification number, patent number, application date, authorization announcement date, license type and duration, and application date.
If the patent licensing contract is changed, dissolved or revoked after filing, China National Intellectual Property Administration shall make corresponding registration and announcement.
Article 17
Where the term of exploitation license expires or the patent exploitation license contract is terminated prematurely, the parties concerned shall, within 30 days after the term expires or the termination agreement is concluded, go to China National Intellectual Property Administration for filing and cancellation with the filing certificate, termination agreement and other relevant documents.