Legal analysis: Generally speaking, as long as the contract is the expression of the true meaning of both parties, it is valid. Failure to stamp is only a procedural matter, but failure to stamp cannot deny the validity of the contract itself. Conditions to be met for a valid contract:

1, the parties have corresponding capacity for civil conduct.

2. The intention of the parties is true.

3, does not violate the law or social public interests.

4. The subject matter of the contract must be definite and possible.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 489 An acceptance to make an immaterial change in the contents of an offer is valid, unless the offeror raises an objection in time or the offer indicates that the acceptance shall not make any change in the contents of the offer, and the contents of the contract shall prevail.

Article 490 Where the parties conclude a contract in the form of a contract, the contract is formed when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it. A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established.