Feynman Upgrade

Overview

This upgrade contains changes such as:

Improve compatibility with EVM:
- The blockhash opcode will now return the actual block hash, instead of a pseudo-random hash derived from the chain ID and block number.
- The ecPairing precompile will now be fully compatible with Ethereum’s version, we remove the previous input limits.
- Adopt EIP-2935: Serve historical block hashes from state from Pectra. This system contract will allow smart contract devs to access to most recent 8191 block hashes. This EIP also plays a key role in restoring the blockhash opcode’s original behavior.
- Adopt EIP-7623: Increase calldata cost from Pectra.
Gas fee parameter redesign
Post Euclid clean-ups

Please note that EIP-7702 from Pectra has been supported since the Euclid upgrade.

Migrating from halo2 to OpenVM allowed removal of some previous limitations of the protocol, including transaction skipping. In Feynman, skipping is removed, as well as old codec versions from previously deployed smart contracts.

Timeline

Scroll Sepolia : Jul 22nd, 2025
Scroll Mainnet : Aug 19th, 2025

Compatibility

This release updates the embedded hard fork block timestamp for Scroll mainnet. Nodes that are not upgraded will be unable to follow the network after the hard fork block.

To follow the Feynman upgrade, simply run your node with the --scroll flag for mainnet (and --scroll-sepolia for testnet).

If you do not use the --scroll flag, then you must update and reimport genesis.json.

Genesis.json difference :

{
  "config": {
    "chainId": 534352,
...
    "euclidTime": 1744815600,
    "euclidV2Time": 1745305200,
    "feynmanTime": 1755576000,
...
"scroll": {
...
      "genesisStateRoot": "0x08d535cc60f40af5dd3b31e0998d7567c2d568b224bed2ba26070aeb078d1339",
      "missingHeaderFieldsSHA256": "0xfa2746026ec9590e37e495cb20046e20a38fd0e7099abd2012640dddf6c88b25"
...

Node Operators

Mandatory changes:

--gpo.congestionthreshold is deprecated and should be removed.

Recommended changes:

Enable the direct-to-sequencer endpoint using --gossip.sequencerhttp <sequencer-url>. This reduces latency for transaction submission.
- Scroll mainnet: --gossip.sequencerhttp https://mainnet-sequencer-proxy.scroll.io
- Scroll Sepolia: --gossip.sequencerhttp https://sepolia-sequencer-proxy.scroll.io

For nodes running with --rollup.verify or --da.sync:

Enable the AWS S3 blob data source using --da.blob.awss3 <s3-bucket-url>. This can be used alongside other blob data sources (da.blob.beaconnode, da.blob.blobscan, da.blob.blocknative).
- Scroll mainnet: --da.blob.awss3 https://scroll-mainnet-blob-data.s3.us-west-2.amazonaws.com
- Scroll Sepolia: --da.blob.awss3 https://scroll-sepolia-blob-data.s3.us-west-2.amazonaws.com

See more details in the testnet release notes.

Dapps and Indexers

While Feynman introduces several contract changes, most of them are internal. Projects that decode batches can continue using the current EuclidV2 codec, however the batch version will become v8.

Maintainers of smart contracts that rely on the blockhash opcode must carefully consider the impact of the change in this opcode’s behavior on their dapp.

Finally, any projects that do off-chain fee computation (instead of relying on RPC queries) should review the new fee formula 1 2 and update their system accordingly.

Projects requiring additional guidance should open a ticket on Discord.

What's Next

Euclid Upgrade