> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stackone.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Customer.io Changelog

> Release history for the Customer.io connector. Each version lists what changed and which actions were affected.

<Card title="Customer.io connector" icon="arrow-left" href="/connectors/customerio" horizontal>
  Back to the connector overview, authentication methods, and actions.
</Card>

<Update label="v2.0.0" description="28 Jul 2026">
  `auth-improvements`

  Split the single API Key auth into two separate auth methods - App API Key (bearer) and Track API Key (basic) - so each shows only its own required fields and test action.
</Update>