How to Resolve Joomla Pre-Update Check Warnings

Start by separating blockers from recommendations

Open System → Update → Joomla and review the Pre-Update Check. Work through the sections in this order:

1. Required Settings — resolve failed requirements before attempting the upgrade.
2. Recommended Settings — investigate warnings and decide whether the server should be adjusted.
3. Extensions — verify compatibility, required updates, and unknown compatibility results for third-party code.

Take a screenshot or record the current warnings before making changes. That gives you a baseline and makes it easier to confirm which action cleared each warning.

Fix PHP and database requirement failures at the server level

If the target Joomla version requires a newer PHP or database version, the fix normally happens in your hosting control panel or with your hosting provider. Confirm that the website itself is using the new PHP version after you change it; command-line PHP and the web server can use different versions.

Before raising PHP on production, check third-party extension compatibility with that PHP version. An old extension can fail on the newer PHP release even when Joomla core supports it.

If the database server is below the target Joomla requirement, do not try to work around the requirement with a Joomla setting. Plan a database server upgrade or move the site to a compatible environment.

Fix Joomla database schema warnings before upgrading

When Joomla reports that its database table structure is not current, go to System → Maintenance → Database. Joomla compares the installed core schema with the schema expected by the current Joomla version.

1. Create a database backup.
2. Open the Database maintenance screen.
3. Review the reported inconsistencies.
4. Use Joomla's database structure update/repair action.
5. Reload the screen and confirm the Joomla core schema is current.
6. Return to the Pre-Update Check and verify that the warning has cleared.

This repairs Joomla core schema differences. It does not validate every third-party extension table.

Resolve extension warnings one extension at a time

For an extension that says an update is required, go to System → Update → Extensions, refresh the update information if necessary, and install the extension version required by the developer before the Joomla upgrade.

For an extension whose compatibility information is missing or unavailable:

• identify the exact extension and installed version under System → Manage → Extensions;
• check the extension developer's release notes and Joomla compatibility statement;
• verify whether the extension uses an active update site;
• check whether a newer version adds compatibility with the target Joomla release;
• test the extension on a staging copy running the intended Joomla and PHP versions.

Missing compatibility metadata is not proof that an extension will fail, but it is also not evidence that the extension is safe.

Pay special attention to plugins that can run during the upgrade

System, authentication, user, installer, task, and other early-running plugins can break an upgrade before Joomla finishes replacing files and updating the database. If the Pre-Update Check flags a plugin as a potential upgrade issue, verify it with the developer and disable it before the upgrade when that is the supported migration procedure.

Do not disable security, authentication, or system plugins on production without understanding the effect. Test the change on staging first, especially when the site uses custom login, SSO, firewalls, access-control software, or external identity providers.

Resolve Joomla 5.4 to Joomla 6 compatibility-plugin warnings correctly

For the Joomla 5.4 to Joomla 6 upgrade, the Pre-Update Check verifies Joomla's backward-compatibility plugins. The Joomla 5 Behaviour - Backward Compatibility plugin should be disabled, while Behaviour - Backward Compatibility 6 should be enabled.

If the Joomla 5.4 site stops working after disabling the older compatibility plugin, turn it back on and find the extension or custom code that still requires it. Do not proceed with the Joomla 6 upgrade until the site works correctly with the old compatibility layer disabled.

Run the check again and verify the upgrade on staging

After each group of corrections, return to the Joomla Update screen and review the Pre-Update Check again. A warning that remains after an extension update may indicate stale update metadata, an inactive update site, or a package containing multiple child extensions with different compatibility information.

When all hard blockers are resolved and every remaining warning is understood, create a fresh full backup and test the exact upgrade on a staging copy. Test the frontend, Administrator, templates, login, forms, scheduled tasks, email, integrations, and business-critical extensions before approving the same upgrade for production.