The Holocene Network Upgrade contains three changes:

• Holocene block derivation: a set of changes that render the derivation pipeline stricter and simpler, but also improve worst-case scenarios for Fault Proofs and Interoperability.
• EIP-1559 configurability: The elasticity and denominator EIP-1559 parameters become configurable via the SystemConfig L1 contract, allowing gas target and gas limit to be independently configured.
• MIPS contract upgrade: Updates to support additional calls made by the new op-program version.

If this vote passes, the Holocene upgrade will be planned for execution on the 9th of Jan 2025 18:00:01 UTC. The upgrade will occur automatically for chains on the Granite mainnet release if those chains have opted-in to activate at Superchain times via their superchain-registry configuration (i.e., have the superchain_time set to a timestamp before or at the mainnet activation time, or have set their holocene_time directly). The mainnet release will be prepared at a later time during the governance process, but no later than 4 weeks before the proposed activation time.

Holocene is code complete in the optimism monorepo at a tag op-node/v1.10.2-rc.1 and op-geth at tag op-geth/v1.101411.4-rc.2.

This proposal is eligible for Special Voting Cycle #31a:

If passed in the Token House, it will proceed to a veto period in the Citizens’ House.