OpenCart 3 vs OpenCart 4: Full Comparison, New Features, and Updates (2025 Guide)

OpenCart is one of the most widely used eCommerce platforms, especially in countries like Bangladesh, India, and many European markets. Over the years, OpenCart 3 has been known for its stability, flexibility, and huge extension ecosystem.
However, with the launch of OpenCart 4, developers and store owners are now seeing a completely new and modern approach to the platform.

So the big questions are:

  • What’s new in OpenCart 4?

  • How is OpenCart 4 different from OpenCart 3?

  • Should you upgrade or start your store with OpenCart 4?

In this detailed 2025 guide, we will compare OpenCart 3 and OpenCart 4 side by side, explaining all major updates, improvements, and developer changes.

What’s New in OpenCart 4? (Latest 2025 Update)

OpenCart 4 brings a range of major improvements and structural changes to make the platform more modern, secure, and developer-friendly.

1. Fully Redesigned Extension System (No OCMOD)

OpenCart 4 removes the old OCMOD override system and introduces a pure events-based override mechanism.
Benefits:

  • Fewer conflicts between extensions

  • More secure and stable

  • Modern and cleaner approach

  • Easier debugging

This is one of the biggest improvements for developers.

2. Admin and Catalog Are Now Separate Applications

OpenCart 4 splits the application into two separate systems:

  • Admin application

  • Catalog (frontend) application

Advantages:

  • Improved security

  • Faster performance

  • Better organization of files

  • Easier maintenance and upgrading

3. Full PSR-4 Namespace Support

OpenCart 4 now follows modern PHP standards with PSR-4 namespaces across:

  • Controllers

  • Models

  • Libraries

  • Events

This makes module development cleaner and more future-proof.

4. Upgraded Twig Template Engine (Twig 3)

OpenCart 3 used Twig 2, while OpenCart 4 upgrades to Twig 3, which offers:

  • Faster rendering

  • Stronger security

  • Better template management

  • Modern syntax

This is a significant enhancement for theme developers.

5. Stronger Security System

OpenCart 4 puts a heavy focus on security:

  • Improved CSRF token protection

  • Better file upload validation

  • Sandbox environment for module installation

  • Cleaner routing & permission handling

6. New Standard Payment & Shipping API

Payment gateways in OpenCart 4 now follow a unified, standard API, making integrations:

  • Faster

  • More stable

  • Easier to maintain

This is very helpful for developers creating custom payment modules.

7. Improved Event System (More Powerful Than OpenCart 3)

  • Multi-level priority

  • Advanced override control

  • Better performance

Events are now the primary way to modify OpenCart behavior instead of OCMOD.

8. Built-in Jobs / Scheduled Tasks System

OpenCart 4 introduces a new jobs system similar to cron jobs.
It allows automated tasks like:

  • Stock syncing

  • Report generation

  • Cache cleaning

  • Sending scheduled emails

9. Better Multi-Store & Multi-Language Support

OpenCart 4 has improved settings & more flexible management of stores and languages.

10. Developer-Friendly Improvements

Some notable updates:

  • Cleaner file structure

  • Better error reporting

  • Improved debugging tools

  • Better routing architecture

  • Updated APIs

OpenCart 4 is clearly built with developers in mind.

OpenCart 3 vs OpenCart 4 — Full Comparison Table

Feature OpenCart 3 OpenCart 4
Extension System OCMOD + Events Events only (No OCMOD)
Namespaces Partial Fully PSR-4
Theme Engine Twig 2 Twig 3
Admin Structure Combined Separated applications
Security Basic Advanced CSRF + File Validation
Payment API Older structure Unified, modern API
Cron Jobs Not included Yes (Jobs system)
Performance Good Faster
Module Compatibility High Partial (Needs updates)
Development Standard Basic MVC Modern MVC-L + Namespace
SEO Support Normal Improved URL routing

Why Choose OpenCart 4?

OpenCart 4 is a great choice if you want:

  • Modern PHP coding standards

  • Stronger security

  • Faster performance

  • Better long-term growth

  • Clean extension development

For new stores, OpenCart 4 is a solid future-proof option.

Limitations of OpenCart 4

Before switching, keep these points in mind:

  • Many OpenCart 3 extensions do not work directly in OpenCart 4

  • Requires redevelopment or rewriting modules

  • Theme compatibility is still limited

  • Developers must learn the new namespace structure

If you need maximum compatibility, OpenCart 3 is still more stable.

Conclusion

OpenCart 4 is a significant upgrade with modern architecture, enhanced performance, advanced security, and improved developer features. While OpenCart 3 remains stable and widely used, OpenCart 4 is clearly the future of the platform.

If you’re building a new eCommerce website, OpenCart 4 is an excellent choice.
If you already have a store on OpenCart 3, upgrading should be done carefully due to compatibility issues.