How to Prepare a Joomla 5 Site for Joomla 6
Bring Joomla 5 to the supported migration starting point
Prepare the site on Joomla 5.4 before moving to Joomla 6. Update Joomla 5 and the site's extensions through their supported paths first, and resolve existing Administrator, database, update-site, and PHP errors before beginning the major-version upgrade.
Verify the Joomla 6 server requirements
Confirm the production and staging environments meet Joomla 6 requirements. Current official requirements list PHP 8.3.0 as the supported minimum and PHP 8.4 as recommended. Also verify the database and web-server versions and required PHP modules rather than assuming a host that ran Joomla 5 is automatically ready for Joomla 6.
Inventory extensions, templates, overrides, and custom code
List every installed third-party package, component, module, plugin, template, library, and custom integration. Check each vendor's Joomla 6 support statement and required upgrade order. Remove unused software only through its supported uninstall process and only after confirming that no data or dependencies are still needed.
Run the Joomla Pre-Update Check
Open System → Update → Joomla and review the checks for the Joomla 6 target. Resolve required environment failures and investigate extension compatibility information. Missing compatibility information is not proof that an extension is safe; verify it with the developer and with a real staging upgrade.
Set the compatibility plugins correctly
For the Joomla 5.4 to 6.x transition, Joomla requires the Joomla 5 Behaviour - Backward Compatibility plugin to be disabled and Behaviour - Backward Compatibility 6 to be installed and enabled. If the Joomla 5.4 site breaks when the Joomla 5 compatibility plugin is disabled, re-enable it and fix the incompatible extension or custom code before attempting Joomla 6.
Create and prove a restorable backup
Take a complete backup of files and database and verify that you can restore it. Joomla's backward-compatibility policy does not support downgrading after an upgrade; restoring the pre-upgrade backup is the safe recovery path when a major upgrade must be reversed.
Perform a full staging rehearsal
Clone production, reproduce the target PHP and database environment, perform the complete Joomla 5.4 to 6 upgrade, and test Administrator, frontend, authentication, content editing, templates, forms, search, scheduled tasks, email, APIs, payments, and other critical extension workflows. Fix the staging failures before scheduling production.
Need More Help with Joomla?
Still having trouble? Open a support ticket with QuantaCade Support and we'll be happy to help where we can.
Support priority is given to QuantaCade products, services, and customers. However, we're also happy to assist fellow Joomla users with general Joomla questions and troubleshooting when possible.
QuantaCade is an independent Joomla extension developer and is not official Joomla support. Some issues involving third-party extensions, hosting environments, server configurations, or other systems outside our development control may be beyond what we're able to resolve.