Do I need to upgrade my Shopify customer accounts to use MESA?

No. MESA works with your store regardless of whether you use Shopify's legacy customer accounts or new customer accounts.

You don't need to migrate before installing MESA or before building workflows.

MESA connects to your store through Shopify's API and webhooks, which operate at the platform level.

The customer account system your storefront uses doesn't change which triggers fire, which actions run, or what MESA can access.