The ArbOS 40 “Callisto” upgrade integrates Ethereum’s Pectra features into Arbitrum and is now active on both Arbitrum One and Nova, introducing advanced primitives for account abstraction, zero-knowledge tooling, and enhanced developer experience across Ethereum’s largest Layer-2 ecosystem

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The Ethereum Pectra Upgrade is reshaping how developers and applications function across the layer-2 environment.

Arbitrum has integrated the Ethereum Pectra Upgrade through its latest ArbOS 40 “Callisto” deployment. This major enhancement is now active on Arbitrum One and Nova. It introduces account abstraction, zk tooling, and developer-focused improvements to Ethereum’s largest layer-2 ecosystem.

A new upgrade, ArbOS 40 "Callisto," unlocks powerful new primitives for account abstraction, zk tooling and developer UX.