Optimism proposes Super Root fault proofs and OPCM v8 upgrade

What happened

OP Labs submitted Upgrade 20 for governance consideration, proposing L1 contract changes to fault proofs and the upgrade manager.

What changed

New dispute games would use Super Roots. Permissionless chains would switch to game type 9; permissioned chains would use type 5, which resolves immediately for the defender while retaining the air-gap and Guardian blacklist.

What did not change

The proposal does not enable interoperability or require an L2 hardfork. Previously submitted withdrawal proofs and existing games remain supported under the proposed design.

Confirmed

• The proposal includes OPCM v8 upgrade-path enforcement and SystemConfig cleanup.
• It targets Sepolia execution on September 17 and mainnet execution on September 24, subject to approval and testing.

Still open

• Governance approval, completed rehearsals, signatures and actual execution are unverified.
• Operational readiness of withdrawal tooling and fault-proof services requires review.

What it means for an advisor

• Review the Optimism bridge memo's dispute-game, upgrade-authority and withdrawal-tooling assumptions before the planned mainnet cutover.
• Do not treat the permissioned-game design as proof that OP Mainnet's withdrawal challenge period has already been bypassed.