Upgrade MultiGov Contracts

MultiGov is designed to be flexible but stable. Upgrades should be rare and carefully considered due to the system's complexity and cross-chain nature. When upgrades are necessary, they must be meticulously planned and executed to ensure system integrity and continuity.

Key Considerations for Upgrades

• HubGovernor:

  • Not upgradeable. A new deployment requires redeploying several components of the MultiGov system. Refer to the Process for Major System Upgrade section for more details

• HubVotePool:

  • Can be replaced by setting a new HubVotePool on the HubGovernor
  • Requires re-registering all spokes on the new HubVotePool
  • Must register the query type and implementation for vote decoding by calling registerQueryType on the new HubVotePool
  • A new proposal would have to authorize the governor to use the newly created hub vote pool and will also handle registering the appropriate query decoders and registering the appropriate spoke SpokeVoteAggregators

• SpokeMessageExecutor:

  • Upgradeable via UUPS proxy pattern
  • Stores critical parameters in SpokeMessageExecutorStorage

• HubEvmSpokeAggregateProposer:

  • Needs redeployment if HubGovernor changes
  • Requires re-registering all spokes after redeployment

• HubProposalMetadata:

  • Needs redeployment if HubGovernor changes, as it references HubGovernor as a parameter

• SpokeMetadataCollector:

  • Requires redeployment if the hub chain ID changes or if HubProposalMetadata changes

Process for Major System Upgrade

1. New HubGovernor deployment:
   • Deploy the new HubGovernor contract
2. Component redeployment:
   • Redeploy HubEvmSpokeAggregateProposer with the new HubGovernor address
   • Redeploy HubProposalMetadata referencing the new HubGovernor
   • If hub chain ID changes, redeploy SpokeMetadataCollector on all spoke chains
3. HubVotePool update:
   • Set the new HubVotePool on the new HubGovernor
   • Register all spokes on the new HubVotePool
   • Register the query type and implementation for vote decoding (HubEvmSpokeVoteDecoder)
4. Spoke re-registration:
   • Re-register all spokes on the new HubEvmSpokeAggregateProposer
5. Verification and testing:
   • Conduct thorough testing of the new system setup
   • Verify all cross-chain interactions are functioning correctly
6. System transition and deprecation:
   • Create a proposal to switch the timelock to the new governor
   • Communicate clearly to the community what changes were made
7. Monitoring:
   • Implement a transition period where the new system is closely monitored
   • Address any issues that arise promptly

Important Considerations

• Always prioritize system stability, upgrades should only be performed when absolutely necessary
• Thoroughly audit all new contract implementations before proposing an upgrade
• Account for all affected components across all chains in the upgrade plan
• Provide comprehensive documentation for the community about the upgrade process and any changes in functionality
• Always test upgrades extensively on testnets before implementing in production