OP Labs tweeted that the upgrade of the Optimism Goerli testnet to Bedrock will start at 02:00 on January 13, Beijing time, and the upgrade will take about 2 hours. This upgrade is similar to a hard fork. The new Optimism Goerli chain will be a continuation of the old chain, and there will be no "regeneration" event in which historical transaction data is lost and the chain is reset at block 0. During the upgrade period, deposits and withdrawals on the previous Optimism Goerli test network will be suspended, transactions on the previous Optimism Goerli sequencer will be stopped, smart contracts on Layer1 will be upgraded, and an unconventional state transition will be carried out on Layer2. At the same time, this upgrade will start the Bedrock sequencer, reopen deposit and withdrawal functions, and distribute contract addresses, binaries, and data directories that interact with the new system. This upgrade will reduce gas fees by approximately 20%, shorten deposit times, build a more secure and stable codebase and product, and simplify node infrastructure. In addition, according to the official upgrade guide, the Optimism mainnet upgrade will announce the official date and time of February 2023 at least three weeks in advance.