If you want to change the default behavior of a module classes and be sure that these changes won't be overwritten during the module upgrade process, you can create your own custom classes. Note, that for more compatibility with future module versions it's recommended to use custom filters instead.
To create custom class copy the original class that you are going to customize to the <prestashop-root>/modules/retailcrm/custom/classes directory.
From here you can modify the methods of the classes for your own purposes, and they will not be affected during the module upgrade process.
Keep in mind that:
- If the logic and classes of the module have changed a lot after an upgrade, your customized logic may cause the module to malfunction. You should always check for changes after an upgrade and update your customized classes if needed.
- This feature does not allow to customize the base class (file
retailcrm.php). For this you can use the standard Prestashop override feature.