Bernoulli Upgrade
Overview
This upgrade features a significant reduction in transaction costs by introducing support for EIP-4844 data blobs and supporting the SHA2-256 precompile.
Timeline
- Scroll Sepolia
- Network Upgrade: April 15th, 2024
- Scroll Mainnet
- Upgrade Initiation: April 15th, 2024
- Timelock Completion & Upgrade: April 29th, 2024
Technical Details
Contract changes
The contract changes for this upgrade are in this PR, along with the audit fixes here. The main changes are as follows:
ScrollChain
now accepts batches with either calldata or blob encoding incommitBatch
.ScrollChain
now supports finalizing blob-encoded batches throughfinalizeBatchWithProof4844
.MultipleVersionRollupVerifier
can now manage different on-chain verifiers for each batch encoding version.
Node changes
The new node version is v5.3.0
. See here for the release log.
zkEVM circuit changes
The new version of zkevm circuits is v0.10.3
. See here for the release log.
Audits
Compatibility
Sequencer and follower nodes (l2geth)
This upgrade is a hard fork as it introduces the new blob data type and the SHA2-256 precompiled contract. Operators running an l2geth
node are required to upgrade before the hard fork block. See the node releases for more information.
Indexers and Bridges
This upgrade changes the format that Scroll uses to publish data to Ethereum. Projects that rely on this data should carefully review the new data format, and check whether their decoders need to be adjusted. A summary of the new format:
- The format of
BlockContext
will not change. Chunks
will no longer include the L2 transaction data. This will instead be stored in a blob attached to thecommitBatch
transaction.BatchHeader
now contains one new field,BlobVersionedHash
.
Provers
This upgrade involves a breaking change in zkevm-circuits. Operators running a prover node are required to upgrade.
Bridge Upgrade
Overview
To reduce bridging costs, we implemented several gas optimizations on our bridge and rollup contract suite. The optimization techniques used include the following:
- We will now use constants to store some companion contract addresses, instead of using storage variables. This is possible since these values should (almost) never change. With this change we can save on a few storage load operations.
- We updated the intrinsic gas estimation in
L1MessageQueue
to use a simple upper bound instead of an exact calculation. The two results will be similar for most bridge transactions but the new implementation is significantly cheaper. - We merged two contracts
L1MessageQueue
andL2GasPriceOracle
to save on call costs from one contract to the other.
Timeline
- Scroll Sepolia:
- Network Upgrade: January 19, 2024
- Scroll Mainnet:
- Upgrade Initiation: February 7, 2024
- Timelock Completion & Upgrade: February 21, 2024
Technical Details
Code Changes
- Bridge Cost Optimization
- Audit Fixes
- Previously deployed version (commit
ff380141a8cbcc214dc65f17ffa44faf4be646b6
) - Version deployed (commit
6030927680a92d0285c2c13e6bb27ed27d1f32d1
)
Audits
List of Changes
Changes to L1 contracts:
- In
ScrollChain
, changemessageQueue
andverifier
toimmutable
. - In
L1ScrollMessenger
, changecounterpart
,rollup
, andmessageQueue
toimmutable
. - In all token gateways, change
counterpart
,router
, andmessenger
toimmutable
. - Merge
L1MessageQueue
andL2GasPriceOracle
into a single contractL1MessageQueueWithGasPriceOracle
(deployed on the same address as the previousL1MessageQueue
). In this contract, we also changemessenger
andscrollChain
toimmutable
, and simplifycalculateIntrinsicGasFee
.
Changes to L2 contracts:
- In
L2ScrollMessenger
, changecounterpart
toimmutable
. - In all token gateways, change
counterpart
,router
, andmessenger
toimmutable
.
Contracts affected:
- L1:
L1MessageQueue
,L2GasPriceOracle
,ScrollChain
,L1WETHGateway
,L1StandardERC20Gateway
,L1GatewayRouter
,L1ScrollMessenger
,L1CustomERC20Gateway
,L1ERC721Gateway
,L1ERC1155Gateway
. - L2:
L2ScrollMessenger
,L2WETHGateway
,L2StandardERC20Gateway
,L2GatewayRouter
,L2CustomERC20Gateway
,L2ERC721Gateway
,L2ERC1155Gateway
.
Compatibility
Sequencer and follower nodes (l2geth)
Operators running an l2geth
node do not need to upgrade. The changes in this upgrade will not affect l2geth
.
Dapps and indexers
Dapps and indexers (and similar off-chain infrastructure) that query contracts or rely on contract interfaces would, in most cases, not need to be changed. The majority of the contract changes are internal and/or backward compatible.
If your application depends on L2GasPriceOracle
to monitor how Scroll keeps track of the L2 gas price on L1, from the upgrade block number you will need to start monitoring L1MessageQueueWithGasPriceOracle
.
The original gas price oracle contract will be deprecated: it will no longer be updated or used by the Scroll bridge.
- Ethereum:
L2GasPriceOracle
:0x987e300fDfb06093859358522a79098848C33852
L1MessageQueueWithGasPriceOracle
:0x0d7E906BD9cAFa154b048cFa766Cc1E54E39AF9B
- Sepolia:
L2GasPriceOracle
:0x247969F4fad93a33d4826046bc3eAE0D36BdE548
L1MessageQueueWithGasPriceOracle
:0xF0B2293F5D834eAe920c6974D50957A1732de763