Optimism is a second layer solution for Ethereum. It runs on the Ethereum blockchain and enables faster and cheaper transactions by bundling many transactions and submitting them to the Ethereum blockchain as a single transaction, a technique called Optimistic Rollup .

The Bedrock upgrade is a major update to Optimism that will take place on June 6, 2023, 16:00 UTC . This is a hard fork and will be triggered by a timestamp rather than a block number.

The OP mainnet will be downtime for 2-4 hours during the upgrade. During the outage, transactions, deposits, and withdrawals are suspended, and the OP mainnet chain will not continue to produce blocks. Ordinary users do not need to take any action related to the upgrade other than planning for 2-4 hours of downtime.

The Bedrock upgrade will improve Optimism’s scalability, security and flexibility. Its main advantages include the following.

Reduce costs

Bedrock's optimized data compression strategy to minimize data costs. It also removes all L1 execution gas, reducing L1 data charges to a theoretical minimum. The Optimism team estimates that the upgrade will reduce gas costs by 47%.

Shorter deposit time

Bedrock has introduced support for L1 re-org in the node software, reducing the time users wait for deposit confirmation from 10 minutes reduced to 3 minutes.

Proof modularity

Bedrock will separate the proof system from OP Stack so that Layer 2 using OP Stack can use fault proof (optimistic summary) Or a validity proof (ZK summary, for example, zk-SNARK) to prove the correctness of the transaction.

Better node performance

Bedrock changes block production from "produce a new block for every new transaction" to "produce one every two minutes new block", which allows the cost of Merkle tree updates to be amortized across multiple transactions and improves node performance. After the upgrade, a private Mempool will host transactions waiting to be executed, so there is no need to worry about MEV.

Better EVM

Optimism designed Bedrock to be as close to Ethereum as possible. Multiple deviations from EVM in previous versions of the OP mainnet have been removed, including:

• One transaction produces one block.
• Custom opcode for getting L1 block information.
• Separate L1/L2 cost fields in JSON-RPC API.
• Customized ERC-20 to display ETH balance.

Bedrock also supports EIP-1559, chain reorganization, and other Ethereum features on L1.

Finally, here you can check whether the upgrade has completed. If you are a node operator or developer, you can refer to further instructions here.