This detailed tutorial guides readers through the process of upgrading an Angular-based quiz application from version 11 to 13, integrating it with a Strapi v4 backend for managing quizzes, authentication, and scores. Building upon previous tutorials, it involves setting up new data models and services to align with updated Strapi content types, adding authentication mechanisms, and enhancing the user interface with components like login, signup, and score-tracking features. The tutorial also focuses on modifying existing components and adding new ones, such as toast notifications, to improve user interaction. It concludes with a demonstration of the app's functionality and encourages further development by suggesting additional features like user profile management and score deletion. The source code is available on GitHub for reference, and readers are directed to Strapi resources for further learning.