If the contract signing date is written incorrectly, the parties can negotiate to change it. A contract with an incorrect signing date will be valid as long as it meets the legal requirements for validity. According to Article 143 of the Civil Code that will take effect in 2021, civil legal acts are valid if they meet the following conditions: (1) The actor has the corresponding capacity for civil conduct; (2) The expression of intention is true; (3) Do not violate the mandatory provisions of laws and administrative regulations, and do not violate public order and good customs. According to the first paragraph of Article 490, if the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign, seal or fingerprint the contract. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it. Article 143 of the Civil Code is valid for civil legal acts that meet the following conditions: (1) The actor has the corresponding capacity for civil conduct; (2) The expression of intention is true; (3) It does not violate the compulsory laws and administrative regulations Sexual regulations do not violate public order and good customs. Article 490, Paragraph 1, of the Civil Code: If the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign, seal or fingerprint the contract. Before signing, sealing or fingerprinting, one party has performed its main obligations and the contract is established when the other party accepts it.