CodeIgniter 3-to-4.7.2 Upgrade -- 2

My website, [login to view URL], is running CodeIgniter 3.1.13 on PHP 7. I need it migrated to CodeIgniter 4.7.2 and PHP 8.5 without breaking anything visible to my users or my team. Key points • The user authentication system and the admin panel must behave exactly as they do today—same URLs, same roles, same permissions. • I already hold a full file and database backup, so you will have safe ground to work on a staging copy first. • I am not sure whether any hidden custom plugins or helper classes were added over the years, so an initial audit of the code base is essential before the actual upgrade begins. Your tasks 1. Review the current CodeIgniter 3 project, flag any legacy or incompatible libraries, and propose solutions. 2. Set up a staging environment on PHP 8.5, install CodeIgniter 4.7.2 via Composer, and port all existing functionality. 3. Re-implement or refactor models, controllers, routes, and views where CI4 architecture requires it. 4. Migrate configuration, session handling, and CSRF settings, making sure login, registration, password reset, and the entire admin dashboard work flawlessly. 5. Run unit and functional tests, fix issues that surface, then coordinate the live switch-over with minimal downtime. Deliverables • Fully upgraded project source on CI 4.7.2, ready to deploy on PHP 8.5. • A short migration report describing every change, including any packages you replaced or removed. • Step-by-step deployment guide so I can reproduce the setup if I ever move servers. Acceptance criteria [login to view URL] loads under PHP 8.5 with no fatal errors, all admin features and user logins operate normally, and Lighthouse/DevTools show no deprecated warnings tied to CI3 code. If you have deep CodeIgniter experience and can work methodically with backups and staging, let’s talk timelines.

Project ID: 40421523