Joomla 6 compatibility informations - Gazette | JoomShaper

Joomla 6 compatibility informations

Joomla 4, 5, 6 Updated 5 Nov 2026 2 min read

Yes, Gazette v2.0.5 works on Joomla 6.x with PHP 8.4. However, some of the template's bundled modules still use legacy Joomla classes, so the template needs Joomla's backward compatibility plugin to be active. That is why your site stopped working as soon as you disabled it.

 The steps below assume Joomla 5.4.x, which is the version required before updating to Joomla 6. There are two plugins with similar names, and they behave differently:

  • Behaviour - Backward Compatibility (the Joomla 5 one): the Joomla 6 pre-update check asks you to disable this.
  • Behaviour - Backward Compatibility 6: this must stay enabled, before and after the update. It only becomes active once the site is on Joomla 6.

So while you are still on Joomla 5 with the first plugin disabled, the front end will show an error (Class "JHtml" not found). This is expected and temporary. Once the update to Joomla 6 completes, the "Backward Compatibility 6" plugin takes over and the site works again.

Please follow these steps:

  1. Take a full backup of your site (files and database, use Akeeba Backup for example).
  2. Make sure Gazette (2.0.5), Helix Ultimate and SP Page Builder are updated to their latest versions.
  3. Go to System > Manage > Plugins, search for "Backward", and confirm Behaviour - Backward Compatibility 6 is enabled. This plugin is included from Joomla 5.4 onwards, so if you don't see it, please update to the latest Joomla 5.4.x first.
  4. Disable Behaviour - Backward Compatibility, then immediately run the Joomla 6 update from System > Update > Joomla.
  5. After the update, clear the Joomla cache (System > Maintenance > Clear Cache) and check the site. Keep "Behaviour - Backward Compatibility 6" enabled.

If you want your current site back online first, simply re-enable Behaviour - Backward Compatibility from System > Manage > Plugins. If the administrator area is not reachable either, open the #__extensions table in phpMyAdmin (your table prefix replaces #__), find the row with folder behaviour and element compat, and set enabled to 1.

For more background, Joomla's official upgrade guide explains both plugins and the full process: https://guide.joomla.org/user-guide/migration/joomla-5-to-6-planning-and-upgrade-step-by-step