My live store is running OpenCart 3.x and I want to move to the latest stable version while preserving every bit of functionality already in place. The shop relies on several custom extensions as well as a bespoke theme, so the upgrade has to be handled on a staging copy first, thoroughly tested, and then rolled out to the production site with no downtime for customers. Key points to note • Current version: 3.x • Both custom extensions and a custom theme are active. • All existing customisations must remain intact and fully functional after the update. Deliverables 1. Full site backup and creation of a staging environment. 2. Core upgrade to the latest stable OpenCart release. 3. Refactor-or patch any custom extensions or theme files that break under the new version. 4. Regression testing of checkout, payment, shipping, and all extension features. 5. Seamless migration from staging to live once everything passes. If you are comfortable troubleshooting extension conflicts, handling theme overrides, and ensuring zero data loss, I’d like to get started right away.