PrestaShop 9 Module Compatibility: What Works and How to Check

Upgrading to PrestaShop 9 means every important module should be checked before production: checkout, payments, invoices, SEO, discounts, shipping and back office tools. This guide explains what changed, why older modules can fail, and how to test module compatibility safely.

Why Do Modules Break on PrestaShop 9?

PrestaShop 9 introduced several breaking changes that affect module compatibility:

• Symfony 6.4 migration — many back office controllers have been rewritten. Modules that override legacy admin controllers will break.
• PHP 8.1+ requirement — modules using deprecated PHP 7.x features will trigger errors.
• Twig templates — back office templates have been converted from Smarty to Twig in many areas.
• Removed legacy hooks — some old hooks have been deprecated or removed.
• API changes — the new Admin API uses a different authentication model (OAuth).

How to Check if a Module is PrestaShop 9 Compatible

1. Check the module description — look for "PrestaShop 9" or "PS 9" in the compatibility list
2. Test on staging — install the module on a PS9 staging environment and test all features
3. Check the module PHP code — look for deprecated functions, legacy controller overrides, and PHP 7.x syntax
4. Contact the developer — ask the module author about PS9 support timeline

PrestaShop 9 Compatible Modules from PrestaSOO

Common Module Issues on PrestaShop 9

1. Legacy Admin Controller Override

If a module overrides a legacy admin controller (e.g., AdminOrdersController), it will not work because PS9 uses Symfony controllers for most admin pages. The module must be updated to use Symfony-compatible hooks or CQRS commands.

2. Smarty Template Dependencies

Modules that modify back office templates using Smarty .tpl files may break in areas where PS9 has migrated to Twig. Front office Smarty templates still work with the Classic theme, but not with the new Hummingbird theme.

3. PHP Compatibility

Common PHP 8.x issues include: deprecated dynamic properties, stricter type checking, and removed functions like mysql_* (should use PDO).

Need Help?

If you are planning a PrestaShop 9 migration and need module compatibility advice, read our PrestaShop 9 complete guide or check our PHP version compatibility chart.

How to Declare PrestaShop 9 Compatibility in Your Module

If you develop PrestaShop modules, you must update the compatibility declaration in your module code:

// In your module main PHP file
public $ps_versions_compliancy = [
    "min" => "8.0.0",
    "max" => "9.99.99"
];

Also update your config.xml file:

<compatibility>
  <min>8.0.0</min>
  <max>9.99.99</max>
</compatibility>

How to Test a Module on PrestaShop 9

1. Set up a local PS9 environment using Docker or XAMPP with PHP 8.3
2. Install your module via the back office module uploader
3. Check the error log at /var/log/ or enable PS debug mode: set _PS_MODE_DEV_ to true in config/defines.inc.php
4. Test all module features — install, configure, front office display, uninstall
5. Run on PHP 8.3 strict mode to catch deprecation warnings
6. Test with Hummingbird theme if your module adds front office elements

Full PrestaSOO Module Compatibility Table

PrestaShop 9 Module Compatibility Checklist

Frequently Asked Questions

Do all PrestaShop 8 modules work on PS9?

Not automatically. Modules that only add front office functionality (banners, popups, product page elements) usually work without changes. Modules that override admin controllers or use deprecated PHP 7.x features will need updates.

Where can I check official module compatibility?

Check the module listing on the PrestaShop Addons Marketplace — each module shows its compatible PS versions. Always verify on a staging environment before upgrading production.

What happens if I install an incompatible module on PS9?

PrestaShop will typically show a compatibility warning. In worst cases, the module may cause a fatal PHP error. Enable debug mode before testing incompatible modules, and always have a backup ready.