Preparing for Fjord Breaking Changes

This page outlines breaking changes related to the Fjord network upgrade for wallets and front-end developers, chain operators, and node operators. If you experience difficulty at any stage of this process, please reach out to developer support.

What's Included in Fjord

The Fjord network upgrade includes the following:

• RIP-7212: Precompile for secp256r1 Curve Support, to reduce gas costs of many smart wallet applications.
• Brotli as a channel compression option, for ~5-15% lower data availability costs.
• Parameter changes:
  • Max sequencer drift becomes a constant with value increased to 1800 seconds
  • 10x increased values for MAX_RLP_BYTES_PER_CHANNEL and MAX_CHANNEL_BANK_SIZE (spec)
• The Fjord hardfork activation block includes several transactions to perform all L2 contract deployments, upgrades, enablements, and proxy updates.
• L1 Gas Cost changes:
  • FastLZ based L1 fee cost calculation with an upgraded GasPriceOracle L2 predeploy) to compute it
  • GasPriceOracle gets a new function getL1FeeUpperBound as a cheap new way to calculate an upper bound for the max fee of a new transaction
  • getL1GasUsed method of the GasPriceOracle contract (spec) is being deprecated
  • L1GasUsed field of the transaction receipt (spec) is being deprecated

For Wallets and Front-End Developers

The proposed Fjord upgrade to the PNC Stack and PNC Mainnet changes the formula for estimating the L1 Data Fee component of the PNC Stack Transaction Fee.

• getL1Fee on the GasPriceOracle contract, this gives a more accurate prediction of L1 data fees.
• getL1GasUsed and the corresponding L1GasUsed field of transaction receipts are being deprecated as they no longer accurately reflect gas usage as of Ecotone. The function and field will remain; however, their usefulness is limited as they still assume calldata batching. getL1Fee should be used when trying to predict L1 Data fees.
• getL1FeeUpperBound is a new method to estimate fee upper bounds when sending transactions. It is much cheaper, in gas costs, than previous methods. This is what wallets and front-ends should use in practice in most cases.
• Read the Fjord Formula section of the Transaction Fees page for more information about the new formula.

Your application may need to be updated to account for this change. Read below to learn how specific changes in the Fjord upgrade require updates to your application.

Preparing Your Wallet or Front-End

Changes to the L1 Data Fee formula may affect your application if you are computing this fee component on your own. It's strongly recommended that you use existing tooling to estimate transaction fees instead of computing them yourself.

• If you cannot use existing tooling, use the getL1Fee function on the GasPriceOracle smart contract to compute the L1 Data Fee component of the transaction fee. Avoid implementing the formula yourself, as it may change in the future.
• Alternatively, you should consider using getL1FeeUpperBound if you only need to estimate an upper bound of the L1 fee for the purpose of transaction sending.

For Chain Operators

The proposed Fjord upgrade impacts PNC chains and requires chain operators to upgrade their chain and configure the sequencer for Fjord.

• Max sequencer drift becomes a constant with value increased to 1800 seconds. This gives chain operators more time to respond to L1 node issues without facing a potential L2 chain halt.
• Brotli is now supported as a channel compression option, for ~5-15% lower data availability costs.
• An update of the fee scalars on the SystemConfig is necessary, similar to Ecotone.

--compression-algo value (default: zlib) ($OP_BATCHER_COMPRESSION_ALGO)
The compression algorithm to use. Valid options: zlib, brotli, brotli-9,
brotli-10, brotli-11

For Node Operators

Node operators will need to upgrade to Fjord before the activation date. For Sepolia, the pnc--batcher release v1.7.7 and pnc-geth release v1.101315.2 contain these changes.

These following steps are necessary for EVERY node operator: