Optimism challenger release requires explicit configuration to retain Cannon coverage

What happened

Optimism published challenger software whose default supported game set drops legacy Cannon.

What changed

Upgrading operators must explicitly retain Cannon when required; otherwise their challenger stops playing those games.

What did not change

The release does not establish a mainnet contract upgrade, shortened withdrawal period, or actual loss of challenger coverage.

Confirmed

• Version 1.9.5 defaults to cannon-kona alone.
• The release warns that legacy Cannon participation stops without explicit configuration.
• Super and ZK game changes described in the release prepare for future upgrades.

Still open

• Which relevant production challengers have upgraded and their configured game types.
• Whether any OP Mainnet game currently depends on an operator affected by this default.

What it means for an advisor

• Review the bridge diligence file's challenger-coverage assumptions and obtain configuration evidence before treating operator upgrades as complete.