The tests don't need to be updated, the additional deployment should be added to the end of the array (In your case, instead of "1088": ["canonical", "eip155"],, make it "1088": ["eip155", "canonical"],) to make it compatible with V1 methods (Source)
Update existing chain
This PR updates Metis 1.3.0 deployments adding canonical deployments
Provide the Chain ID (Only 1 chain id per PR).
Provide RPC URL for the chain (should be able to query atleast 10 requests per minute for automatic PR check).
Relevant information: Block exploreres: https://andromeda-explorer.metis.io/ https://explorer.metis.io