Joomla 6 Upgrade: What's New and How to Upgrade Safely
What's New in Joomla 6
Joomla 6 is a long-term-support release focused on performance and modernization rather than a visual overhaul. The admin interface loads faster, the codebase drops support for older PHP versions in favor of PHP 8.1 and up, and several deprecated APIs from Joomla 5 were finally removed. If your site or its extensions still lean on old Joomla 4-era code, that's usually where upgrade problems show up first.
Is Your Site Ready to Upgrade?
Before touching anything, answer three questions: What PHP version is your host running? Which extensions are you using, and are they still maintained? Does your template rely on any deprecated Joomla 5 APIs? A site running current, actively-maintained extensions on PHP 8.1+ is usually a low-risk upgrade. A site still running legacy Joomla 4 extensions needs a compatibility audit first.
Step 1: Check PHP and Server Requirements
Joomla 6 requires PHP 8.1 or higher. Check your current PHP version in Joomla's System Information panel or with your host's control panel, and upgrade it first if needed — ideally on a staging copy, since a PHP version bump can itself break older extensions.
Step 2: Audit Extensions and Template Compatibility
- Check each installed extension's changelog or vendor site for explicit Joomla 6 support.
- Look for extensions that haven't been updated in over a year — these are the most likely to break.
- Confirm your template developer has published a Joomla 6-compatible version.
Step 3: Test on Staging First
Never run a major version upgrade directly on your live site. Clone your site to a staging environment, run the upgrade there, and fix anything that breaks before touching production. This is the single biggest factor in whether an upgrade goes smoothly.
Step 4: Run the Upgrade
Take a full backup, then use Joomla's built-in Update component (or the Joomla Update package) to install Joomla 6 on staging. Watch for warnings during the process — they usually point to the extension or template causing trouble.
Step 5: Post-Upgrade Testing
Once the upgrade completes, test every critical path: forms, checkout if you run e-commerce, custom components, and the admin panel itself. Check the browser console for JavaScript errors and your server logs for PHP warnings.
Common Upgrade Issues and How to Avoid Them
Most Joomla 6 upgrade failures trace back to one of three causes: an extension using a removed Joomla 5 API, a template built against an old Bootstrap version, or a PHP version mismatch between staging and production. Auditing extensions and PHP compatibility before you start avoids nearly all of them.
When to Get Expert Help
If your site runs custom components, has heavy third-party integrations, or you simply can't afford downtime, it's worth having a Joomla upgrade specialist handle the compatibility audit and staging upgrade for you. We've run this process on 100+ sites and know exactly where Joomla 6 tends to trip people up.