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    Recurring Billing Developer Guide
    This section describes how to use this guide and where to find further information.
- Audience and Purpose
 - This guide is for merchants who use the upgraded or newNational Australia BankRecurring Billing service. The service is available through theGateway Portaland the REST API.
 - Conventions
 - This statement appears in this document:IMPORTANTAnImportantstatement contains information essential to successfully completing a task or learning a concept.