A customer is uploading a new application to Google Play and wants to reuse the Application ID of another unlisted app. What is the expected behavior?

Google Play enforces a strict rule that each Application ID (also known as package name) must be unique across all applications published on the platform, regardless of their listing status (public or unlisted). This ID is a fundamental identifier for an app, used for updates, licensing, and inter-app communication. Attempting to upload a new application with an Application ID that is already in use by another app, even an unlisted one, will result in rejection. Google Play does not replace existing apps based on ID reuse, nor does it automatically generate new IDs in such cases. Therefore, the upload will fail.