ENSRegistryWithFallback

import '@ensdomains/ens-contracts/contracts/registry/ENSRegistryWithFallback.sol';

contract MigrationExample {
    ENSRegistryWithFallback public registry;

    constructor(ENSRegistryWithFallback _registry) {
        registry = _registry;
    }

    function checkOwner(bytes32 node) public view returns (address) {
        // This will check the new registry first,
        // then fall back to the old registry if not found
        return registry.owner(node);
    }

    function getResolver(bytes32 node) public view returns (address) {
        // Same fallback behavior
        return registry.resolver(node);
    }

    function recordMigrated(bytes32 node) public view returns (bool) {
        // Check if record exists in new registry
        return registry.recordExists(node);
    }
}

import '@ensdomains/ens-contracts/contracts/registry/ENSRegistryWithFallback.sol';

contract RecordMigration {
    ENSRegistryWithFallback public newRegistry;

    constructor(ENSRegistryWithFallback _newRegistry) {
        newRegistry = _newRegistry;
    }

    function migrateRecord(bytes32 node) public {
        // Get current values (from old or new registry)
        address currentOwner = newRegistry.owner(node);
        address currentResolver = newRegistry.resolver(node);
        uint64 currentTTL = newRegistry.ttl(node);

        // Only the owner can migrate their record
        require(msg.sender == currentOwner, "Not the owner");

        // Set the record in the new registry
        // This makes it no longer fall back to the old registry
        newRegistry.setRecord(
            node,
            currentOwner,
            currentResolver,
            currentTTL
        );
    }
}