Quick answer: The Joomla core upgrade from 5.4 to 6 is usually the easy part. What goes wrong is the extensions, templates and custom code sitting on top of it. Before you upgrade, take a full backup, create a staging copy, list every extension and template, check each one for Joomla 6 support (using the Pre-Update Check, the Joomla Extensions Directory and the developer’s own release notes), sort them into ready, ready with the backward compatibility plugin, waiting on an update, and abandoned, then fix or replace the problem items and test on staging before you touch your live site. With Joomla 5 now in its security-only phase, it is a good time to start this audit.
Why extensions decide whether your upgrade succeeds
Joomla 5 stopped receiving regular bug fixes on 13 October 2026. It continues to receive security fixes until 12 October 2027, so your site is not in immediate danger. But from now on, ordinary bugs, compatibility problems with newer PHP or database versions and extension conflicts are no longer fixed in Joomla 5.
The Joomla project describes the move from Joomla 5.4 to Joomla 6 as an upgrade rather than a full migration, which is good news. That description depends on your extensions having removed deprecated code and being built for current Joomla. In practice, the usual blockers are:
- A page builder or template framework without a Joomla 6 release
- A commercial extension whose licence or update subscription has lapsed
- An abandoned extension that has not been updated for years
- Custom code written for older Joomla versions
- Template overrides that no longer match the updated core files
- Hosting that does not meet the new PHP or database requirements
If you want the bigger picture first, read our guides to upgrading from Joomla 5 to Joomla 6 and Joomla end of life. This article is the detailed audit that sits between “we should upgrade” and “we are ready to upgrade”.
What you need before you start
- Administrator access to your Joomla site, and to your hosting control panel or server
- A recent full backup of the files and database
- A staging site, which is a private copy of your live site where you can test safely
- A spreadsheet or document to record your findings
- Login details for any commercial extension accounts, because you may need to download updates
If you are on Joomla 4 or earlier, you will need to move through Joomla 5 first, so start with our Joomla migration guide instead.
The 10-step Joomla 6 extension audit
Step 1: Back up and create a staging copy
Take a full backup using a tool such as Akeeba Backup or your host’s backup system, and store a copy off the server. Then restore it to a staging site. Run every test and every update in this audit on staging first. If something breaks, you want it to break on a copy, not on the site your customers use.
Step 2: Update Joomla and everything on it to the latest 5.4.x
Before you check Joomla 6 compatibility, bring your Joomla 5 site fully up to date. Update core to the latest 5.4.x release, then update all extensions, templates and language packs. This matters for two reasons. First, Joomla’s upgrade path requires you to be on the latest Joomla 5.4 release before moving to 6. Second, many developers release their Joomla 6-ready versions as updates to their Joomla 5 versions, so you may find some compatibility problems disappear after this step.
Step 3: Build a complete inventory
In the Joomla administrator, open the Extensions Manager and list everything installed: components, modules, plugins, templates, libraries and language packs. For each item, record:
- Name and type
- Installed version
- Developer or vendor
- Whether it is free or commercial, and when its update subscription expires
- Whether it is enabled and actually used on the site
- Where updates come from (the extension’s update site)
- The date of its last release
Don’t forget the less visible items: third-party plugins that run in the background, system plugins that inject scripts, and libraries other extensions depend on.
Step 4: Remove what you don’t use
Every extension you remove is one fewer thing to check, update or defend. Look for extensions that are disabled, no longer connected to any menu item or module, or left over from an old redesign. Uninstall the ones you no longer need, and check for leftover files and database tables. This also reduces your security exposure. Our guide to Joomla maintenance and security explains why a smaller extension footprint is safer.
Step 5: Check each extension’s Joomla 6 status
There are four reliable places to look:
- Joomla’s Pre-Update Check. In the Joomla Update component, the pre-update check lists compatibility information for installed extensions, based on what each developer reports through its update site. Treat it as a useful first pass, not a final answer, because it depends on developers keeping their update information accurate.
- The Joomla Extensions Directory (JED). You can filter extensions by Joomla version, which helps you see which are marked as ready for Joomla 6 and which are ready only when the backward compatibility plugin is enabled.
- The developer’s own website and changelog. Look for explicit “Joomla 6 compatible” statements, release notes and support forum posts.
- Direct contact. For critical extensions, email the developer and ask about their Joomla 6 plans and dates, and keep the answer for your records.
Step 6: Classify every extension
Sort each item into one of these categories:
| Status | What it means | What to do |
|---|---|---|
| Ready | The developer offers a Joomla 6 version | Update on staging and test |
| Ready with backward compatibility plugin | Works on Joomla 6 only with the compatibility plugin enabled | Test carefully, and plan to move to a native version when available |
| Update pending | The developer has announced Joomla 6 support but not released it | Set a date to re-check, or prepare a fallback |
| Unknown | No clear information | Contact the developer, and test on staging |
| Abandoned | No updates for a long time, no response from the developer | Replace it, or remove the feature |
The backward compatibility plugin is a bridge, not a destination. It can keep an older extension working for now, but it adds risk and may not be supported forever, so treat any extension that relies on it as something to replace or update soon.
Step 7: Audit your template and its overrides
Your template deserves its own check, because it controls how your whole site looks and it often includes a framework or page builder.
- Check the template and framework vendor. Confirm that your template, any template framework and any bundled page builder have Joomla 6 releases.
- Review template overrides. Overrides are custom copies of Joomla’s core layouts stored in your template. When core layouts change, old overrides can break the display or miss security fixes. Joomla’s Template Overrides screen can flag overrides whose core files have changed, so review each one and update or remove it.
- Check custom CSS and JavaScript. Look for scripts that depend on libraries, such as old jQuery plugins, that may no longer be loaded the same way.
- Test on mobile and in accessibility checks. Visual regressions often show up on small screens first. Our Joomla template design and customisation service can help with complex templates.
Step 8: Review custom code
If you have custom components, modules, plugins or snippets, whether built in-house or by a previous developer, they need a developer’s review. Look for:
- Use of deprecated or removed Joomla APIs and classes
- Code that isn’t compatible with the PHP version Joomla 6 requires
- Direct database queries that depend on older conventions
- Hard-coded paths, or code that modifies core files
Static analysis tools such as PHP_CodeSniffer with PHP compatibility rules can find many problems quickly, but a human review is still needed.
Step 9: Confirm your hosting meets the requirements
Joomla 6 raises the minimum PHP and database versions compared with earlier releases. Check the current requirements on the Joomla website and compare them with your host’s PHP version, database version and PHP extensions. If your hosting needs upgrading, do it as a separate, tested step before the Joomla upgrade, so you know whether any problem came from the server or from Joomla. Our guide on speeding up a slow Joomla website also covers PHP and hosting choices.
Step 10: Run the upgrade on staging and test thoroughly
Once your inventory is clean, run the upgrade on staging and test the site like a visitor and like an administrator. Check:
- Home page, key landing pages and the menu structure
- Forms, contact pages and email delivery
- Search, filters and any custom directories or listings
- Login, registration and user permissions
- eCommerce checkout, payment gateways and order emails if you sell online
- Multilingual pages, if used
- Media, downloads and embedded content
- Cache, SEF URLs and redirects
- Backend editing, including the editor and workflows
- Mobile layout and performance
Keep a written list of problems, fix them on staging, and repeat until the list is clear. Only then plan your live upgrade, with a fresh backup and a rollback plan.
Understanding the risk: which extensions need the most attention?
Not all extensions are equally risky. Rank them by what would happen if they broke:| Risk level | Examples | Approach |
|---|---|---|
| High | Page builders, eCommerce, booking, membership, forms with payments, SEF and redirect tools | Audit first, test most thoroughly, have a fallback |
| Medium | Gallery, SEO, backup, security, caching and analytics extensions | Confirm Joomla 6 support, test key features |
| Low | Simple modules, small plugins, decorative features | Update, test quickly, remove if no longer needed |
What to do about extensions that are not ready
When an extension isn’t ready for Joomla 6, you have several options:- Wait, with a deadline. If the developer has confirmed a release date, wait, but set a firm decision date so the whole upgrade doesn’t stall.
- Use the backward compatibility plugin temporarily. This can help for low-risk extensions, as long as you test carefully and plan a proper replacement.
- Replace it. Look for an actively maintained alternative, check its Joomla 6 support in the JED, and migrate your data and settings.
- Rebuild the feature. For simple functions, a lighter approach using Joomla’s built-in features may be better than another extension.
- Remove it. If few visitors use the feature, retiring it is often the cheapest and safest choice.
- Commission an update. For a custom or niche extension, you can hire a developer to update the code.
How long will the audit take?
It depends on how many extensions you have and how heavily the site is customised. As a rough guide:| Site type | Typical audit effort |
|---|---|
| Simple brochure site with a handful of extensions | A day or two |
| Business site with forms, galleries and a custom template | Several days |
| Large site, eCommerce, membership or heavy customisation | One to several weeks |
Common mistakes to avoid
- Upgrading live without testing on staging. This is the most expensive mistake in the list.
- Relying only on the Pre-Update Check. It is a starting point, not a guarantee.
- Skipping the template. A broken template affects every page.
- Enabling the backward compatibility plugin and forgetting about it. Treat it as a temporary measure.
- Leaving unused extensions installed. They add risk and upgrade work.
- Ignoring licences and subscriptions. You may be unable to download updates when you need them.
- Not asking developers directly. A short email can save days of guesswork.
- Waiting until the last minute. Joomla 5 remains secure until October 2027, but rushing an upgrade late in the window leaves no time to solve problems.
DIY or get a Joomla specialist?
If you have a simple site, few extensions and some technical confidence, you can complete much of this audit yourself using the steps above. Bring in a specialist when you have many or critical extensions, a heavily customised template, custom code, an eCommerce or membership site, or limited time. A good Joomla team will audit your site, give you a clear status report for each extension, handle updates and replacements, test on staging and manage the live cutover. Learn more about our Joomla migration and upgrade service, our custom Joomla development and our Joomla maintenance and support plans. If you also want to know what is new in the latest release, see our guide to Joomla 6.2 Mwezi.
Printable checklist
- Full backup taken and stored off the server
- Staging site created
- Joomla and all extensions updated to the latest Joomla 5.4.x versions
- Complete extension, template and library inventory created
- Unused extensions uninstalled and leftovers cleaned up
- Pre-Update Check reviewed
- Each extension checked in the Joomla Extensions Directory
- Developers contacted about unclear or critical extensions
- Extensions classified as ready, backward-compatible, pending, unknown or abandoned
- Template, framework and page builder confirmed for Joomla 6
- Template overrides reviewed and updated
- Custom code reviewed for deprecated functions and PHP compatibility
- Hosting PHP and database versions confirmed
- Licences and subscriptions renewed where needed
- Staging upgrade completed and fully tested
- Live upgrade date, backup and rollback plan agreed
Frequently asked questions
How do I check if my Joomla extensions are compatible with Joomla 6?
Use the Pre-Update Check in the Joomla Update component, filter by Joomla version in the Joomla Extensions Directory, read each developer’s changelog and website, and contact the developer for any extension you can’t confirm. Then test on a staging site.
Is upgrading from Joomla 5 to Joomla 6 a migration or an upgrade?
For most sites on Joomla 5.4, it is an upgrade within the same upgrade system, not a rebuild. That said, how smooth it is depends heavily on whether your extensions and template support Joomla 6.
Do I have to upgrade right now?
Not necessarily. Joomla 5 receives security fixes until 12 October 2027, so your site isn’t at immediate risk. However, regular bug fixes ended on 13 October 2026, and an audit takes time, so it is sensible to start planning now.
What is the backward compatibility plugin?
It is a Joomla plugin that helps older extensions keep working on a newer Joomla version by providing support for older code. It can be a useful short-term bridge, but you should plan to move to extensions that are natively compatible.
What should I do if an extension I rely on has been abandoned?
Look for a maintained alternative, rebuild the function with core Joomla features, hire a developer to update it, or remove the feature if it is no longer essential. Avoid leaving an abandoned extension on a site that handles customer data.
Will my template work on Joomla 6?
Only if the template vendor has released a Joomla 6 compatible version, and any custom overrides have been reviewed. Check the template, its framework and any bundled page builder separately.
Should I upgrade PHP before or after Joomla?
Check Joomla 6’s PHP requirement first. If your server needs a newer PHP version, upgrade it as a separate, tested step before the Joomla upgrade, so you can tell which change caused any problems.
How much does a Joomla extension audit cost?
Costs depend on the number of extensions, the complexity of your template and whether you have custom code. A small site can be quick and affordable, while a large or heavily customised site needs more time. An assessment will give you a clear estimate.
Need help auditing your Joomla site?
Joomla Professionals helps Australian businesses audit, upgrade and maintain Joomla websites. We can review every extension and template on your site, tell you what is ready and what isn’t, and manage the entire upgrade to Joomla 6 with testing and a safe rollback plan.
Contact us to book a Joomla 6 compatibility audit.