The tutorial provides a comprehensive guide on updating an Android app using Couchbase Mobile, emphasizing the use of a Sync Gateway webhook to import data from the Google Places API with Node.js. It details the process of syncing data initially and later restricting data to a subset by modifying access rules in the Sync Function, followed by a resync operation to update these rules. The setup involves installing Sync Gateway, configuring a webhook, building an app server with Node.js and Express, and integrating these with an Android app using the Google Maps SDK and Couchbase Lite for data synchronization. The tutorial also covers creating users and implementing access controls to filter documents per device location, ensuring efficient data management as the application scales. The guide concludes with a demonstration of using the resync endpoint to update document access following changes to the Sync Function, highlighting best practices for managing mobile app updates and user-specific data access.