Upgrade from 3.x to 4.x

Guide to upgrade from OpenCart 3.x to 4.x

Important Notes

Before starting the upgrade process, please note:

• Backup everything: Database and files

• Test in staging environment first

• Check extension compatibility with OpenCart 4

• Review theme compatibility

Pre-Upgrade Checklist

1. Backup your store:

   • Database backup

   • File system backup

   • Extension configurations

2. Check compatibility:

   • Verify PHP version compatibility (PHP 8.0+ required)

   • Check if extensions support OpenCart 4

   • Review theme compatibility

3. Prepare for downtime:

   • Schedule upgrade during low-traffic periods

   • Inform customers about maintenance

Upgrade Methods

Method 1: Manual Upgrade

1. Download OpenCart 4

   • Get the latest version from OpenCart website

2. Upload new files

   • Upload all files except:

     • /config.php

     • /admin/config.php

     • /images/ directory

     • /system/storage/ directory

3. Run upgrade script

   • Navigate to yourdomain.com/install

   • Follow the upgrade wizard

4. Update database

   • The upgrade script will automatically update your database schema

Method 2: Extension-Based Upgrade

Some hosting providers offer extension-based upgrades through their control panels.

Post-Upgrade Tasks

1. Clear cache:

   • Delete /system/storage/cache/ contents

   • Clear browser cache

2. Test functionality:

   • Test frontend and backend

   • Verify all extensions work

   • Check payment and shipping methods

3. Update extensions:

   • Install OpenCart 4 compatible versions

   • Configure settings as needed

Common Issues

• Extension compatibility: Some extensions may not work with OpenCart 4

• Theme issues: Custom themes may need updates

• Database errors: Check error logs for any database-related issues

Support

If you encounter issues during upgrade, visit the OpenCart forums for community support.