Legal analysis: Yes, upgrading a branch to a subsidiary is a brand-new company, which will have a substantial impact on the labor relations of employees who originally belonged to the branch and are now included in the subsidiary. Employees are equivalent to new employees. It is suggested to sign a new labor contract with the original employee in the name of the subsidiary in time. If you don't sign a written labor contract, you will have the legal risk of paying double wages.
Legal basis: Article 17 of People's Republic of China (PRC) Labor Law shall follow the principles of equality, voluntariness and consensus through consultation, and shall not violate the provisions of laws and administrative regulations. After a labor contract is concluded in accordance with the law, it is legally binding, and the parties must fulfill their obligations under the labor contract.