On October 2, Ethereum Classic Labs officially issued a document stating that it is implementing a 51% attack solution MESS (Modified Exponential Subjective Scoring). The core developers and community members have accepted the MESS program, and the program was successfully activated on the Mordor testnet on September 28, and passed strict stress tests and simulated attacks. At the same time, the activation plan of the MESS program on the ETC mainnet will be carried out at the block height of 11380000, and the estimated time is October 10. This solution will be used as a core Geth configuration and will be set in the ETC mainnet v1.11.15 and the above versions. In addition, the official reminder said that this program activation is not a hard fork, but nodes that are not upgraded will not be protected by the program. The MESS security function is only available in the Core-Geth client. Hyperledger Besu and Multi-Geth clients have not yet set the MESS security function. The Besu team is working hard to add this feature in the future. Officials say that Parity Ethereum, OpenEthereum and Geth-Classic clients are not recommended.