The recent ArbOS 40 upgrade, known as 'Callisto', is now available on Arbitrum, expanding the capabilities of the Ethereum network. This update includes new parameters taken from the Pectra hard fork.
ArbOS 40 Update on Arbitrum
The ArbOS 40 'Callisto' upgrade was announced in a recent tweet and is now live on Arbitrum One and Nova. It introduces new capabilities from the Pectra hard fork, including the introduction of EIP-7702 (Account Abstraction), EIP-2537 (BLS Precompile), EIP-2935 (Block Hash Access), and a minor Stylus fix for developers.
New EIP Features in Pectra
EIP-7702 enhances account abstraction on Arbitrum chains. Externally Owned Accounts can temporarily include executable code during transactions. This opens up possibilities for delegation, transaction batching, transaction sponsorship, and sub-key permission control.
ArbOS 40 also incorporates EIP-2537, which introduces precompiles on the BLS12-381 curve, boosting efficiency and security. EIP-2935 adds access to recent block hashes on L2 and improves Trustless messaging, Oracle syncing, and L2 stateless clients.
Consequences of the Update for Ethereum
The Pectra upgrade was activated on the Ethereum mainnet on May 7, 2025. This upgrade enhances the validator experience and supports L2 scalability. A key element of the update is EIP-7691, which doubles the blob throughput, allowing L2s to send compressed transaction data and proofs to Ethereum L1.
The ArbOS 40 update and Pectra integration on Arbitrum represent a significant step toward enhancing Ethereum's functionality and manageability for developers. The new capabilities opened by these updates may impact the further development of layer two networks.
