What is the Optimism Bedrock Upgrade

Optimism is a Layer 2 solution for Ethereum. It runs on top of the Ethereum blockchain, allowing faster and cheaper transactions by bundling many transactions and submitting them to the Ethereum blockchain as a single transaction, a technique called optimistic rollups.

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

The upgrade will require 2-4 hours of downtime for OP Mainnet. Transactions, deposits, and withdrawals will be unavailable for the duration of the downtime, and the OP Mainnet chain will not be progressing.

Regular users need NOT take any actions related to the upgrade beyond preparing for 2-4 hours of downtime on upgrade day.

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

Lower Fees

Bedrock implements an optimized data compression strategy to minimize data costs. It also removes all L1 execution gas, reducing L1 data fees to the theoretical minimum. Together, Optimism estimates a reduction in gas fees by 47%.

Shorter Deposit Times

Bedrock introduces support for L1 re-org in the node software, significantly reducing the time users wait for deposit confirmations from up to 10 minutes to within 3 minutes.

Proof Modularity

Bedrock abstracts the proof system from the OP Stack so that a rollup may use either a fault proof or validity proof (e.g., a zk-SNARK) to prove the correct execution of inputs on the rollup.

Better Node Performance

Bedrock changes block production from "a new block for every new transaction" to "a new block every two minutes." This allows the cost of Merkle tree updates to be amortized across multiple transactions and improves node performance. A private mempool will host the pending transactions after the upgrade, so there is no concern for MEV.

Improved EVM

The Optimism team designed Bedrock from the ground up to be as close to Ethereum as possible. Multiple deviations from the EVM in the previous version of the protocol have been removed, including:

• The one-transaction-per-block model.
• Custom opcodes to get L1 block information.
• Separate L1/L2 fee fields in the JSON-RPC API.
• A custom ERC-20 representation of ETH balances.

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

On a final note, you can check whether the upgrade has been completed and the status of Optimism here. You may refer to further instructions here if you are a node operator or web developer.