Joomla 5 vs Joomla 6: which should you test on?

Test on the version your live site runs today, and get familiar with Joomla 6.1 before October. That is the short answer. The longer one matters. Joomla 6 needs a newer PHP, ships automatic core updates, and stays supported years past Joomla 5.

As of September 2026 the current packages are Joomla 6.1.3 and Joomla 5.4.8, and Joomla 5’s regular support ends in about five weeks. This guide lines up the requirements, the support dates, and the testing question, then shows how to open a free Joomla test site on either version in one click.

What is the difference between Joomla 5 and Joomla 6?

Joomla 6 is the current major line. The Joomla Project announced it on 14 October 2025 in its Joomla 6.0 and Joomla 5.4 are here! release news, which added automatic core updates built on The Update Framework, the Cassiopeia child template, and advanced versioning for custom fields. Joomla 5 is the previous major line, now at 5.4.8. It remains stable and widely deployed while it runs out its support window.

Joomla.org announced the newest minor release in the 6 line, Joomla 6.1 (Nyota), on 14 April 2026 in Joomla 6.1 is here! It shipped a Proof-of-Work CAPTCHA, a Visual Workflow Editor, Media custom fields, and smarter modules. None of those exist in Joomla 5. Our post on what’s new in Joomla 6.1 covers them in full. Joomla 5 will not get an equivalent feature release, because new features land in the current major line rather than the one being phased out.

Both lines are still patched together. In August 2026 the Joomla Project shipped Joomla 6.1.3 and 5.4.8, a combined release covering 10 core security issues and 18 bug fixes. That August 2026 release announcement notes something worth testing, not trusting: most Joomla 5 extensions run on Joomla 6, either directly or through the Behaviour 6 Backward Compatibility Plugin.

What do Joomla 5 and Joomla 6 need to run?

The 2026 Technical Requirements pages in the Joomla Programmers Documentation put the two lines two PHP releases apart. The Joomla 5.4 requirements list PHP 8.1.0 as the minimum and 8.3 as recommended, while the Joomla 6 requirements need 8.3.0 at minimum and recommend 8.4. Both lines want MySQL 8.0.13 or newer and a PHP memory limit of at least 256 MB.

PHP 8.3 is the realistic floor for both lines. The requirements page suggests a wider range, but PHP 8.1 passed end-of-life before 2026 and PHP 8.2 receives security fixes only until 31 December 2026, per The PHP Group’s 2026 Supported Versions page. So a server you would responsibly run Joomla 5.4 on already meets Joomla 6.1’s minimum. Our Joomla system requirements guide has the full list.

We build on that overlap. JInstant defaults every new site to PHP 8.3, because it is the one version that satisfies both lines, so a single default serves a 5.4 test and a 6.1 test equally well. We still keep 8.2 and 8.4 selectable, and the older one earns its place: when you are trying to reproduce what a dated shared host is doing to your Joomla 5 site, matching its PHP matters more than running the newest one available.

A default XAMPP install often ships an older PHP than either line needs, which is one reason a local stack can fall short before you even open the installer. Our guide on trying Joomla without XAMPP covers why, and how a hosted test site sidesteps the version juggling entirely.

Support windows: Joomla 5 ends 13 October 2026

Joomla 5 reaches the end of regular bugfix support on 13 October 2026 and continues with security-only fixes until 12 October 2027. Joomla 6 has regular support through 17 October 2028 and security fixes until 16 October 2029, according to the 2026 Joomla Project Roadmap.

That gap is roughly two years. For what changes on each Joomla 5 date, see Joomla 5 end of life.

The Joomla Project Roadmap also schedules Joomla 6.2.0 for 13 October 2026, the exact day Joomla 5 drops to security-only. Joomla 6.2 is a minor release and is not meant to break backwards compatibility, so 6.1.3 is a sound version to test against today. Roadmap dates are marked tentative, but the Joomla 5 cut-off is close enough to plan around now.

Most sites have not moved yet. In September 2026, W3Techs’ Usage Statistics and Market Share of Joomla put Joomla on 1.1% of all websites, with 52.6% of Joomla installs still on the long-dead version 3, 20.6% on version 5, and only 8.1% on version 6. If your live site sits in that 20.6%, moving to 6 is a question of when you test it, not whether. And if you are in the 52.6% still on Joomla 3, the path runs through 4 and 5 before 6, which is the route our Joomla 3 to 5 migration guide walks through.

Which version should you test extensions and templates on?

Test on whichever version your live site runs today. That is the environment an extension or template update actually has to work in. If you run a live Joomla 5 site in 2026, a clean 5.4.8 install is the right baseline for checking compatibility before you touch production, the same pattern covered in our guide on testing a Joomla extension online.

Cross-version compatibility is worth checking, not assuming. In its August 2026 Joomla 6.1.3 & 5.4.8 Security & Bugfix Release announcement, the Joomla Project said most Joomla 5 extensions work on Joomla 6, either directly or through the Behaviour 6 Backward Compatibility Plugin. “Most” is doing real work in that sentence, and the only way to find out which side of it your extensions fall on is to install them on a 6.1 copy.

Starting a new project, picking a template club, or evaluating Joomla for the first time? Test on 6.1. It has the longer support runway, and new extensions and templates are increasingly built and tested against it, not against the line being phased out. Either way, keep the test off your live install. That is the whole point of a disposable sandbox.

How do you test the Joomla 5 to 6 update before going live?

Test the Joomla 5 to 6 upgrade on a clean copy before attempting it live. It is an in-place upgrade, meaning the same install is updated rather than content being moved to a new one, so the test run is short. Open a throwaway 5.4 site, take it through the update, and check what moved before you repeat it on production. Five steps cover the whole loop.

1. Open a clean Joomla 5.4 test site and log into its Administrator.
2. Install the extensions, template, and any overrides your live site depends on, so the test matches production rather than a stock install.
3. Under System, then Update, then Joomla, set the update channel to Joomla Next. The 6.x package does not appear on the default channel, so the update will not offer itself until you switch.
4. Run the pre-update check and read every warning before you continue, then run the update itself.
5. Re-open the front end and the Administrator. Confirm each extension still loads, and note anything that only works through the Behaviour 6 Backward Compatibility Plugin.

Our step-by-step walkthroughs on how to upgrade Joomla 5 to 6 and testing a Joomla update before going live cover each step in detail. The question this post answers is narrower: which version to test on. Test on a copy of what you run now, and land on 6.1.

Each JInstant test site is a real, isolated install, not a shared demo. You can install extensions, change settings, and break things on purpose with no risk to a live site, and the 4-hour auto-delete means there is nothing to clean up afterward. You open a fresh one the next time you need to check something.

Picking a version for your next test site

For evaluation work in 2026, default to Joomla 6.1. It is the current release, and Joomla 5’s regular support ends 13 October 2026. If your job is specifically to verify Joomla 5 behavior, such as a live site still running it, open a 5.4 test site instead. Matching the version you are actually responsible for matters more than defaulting to the newest one.

Plenty of people want a disposable copy of either. A July 2024 discussion in the joomla/joomla-cms repository on GitHub asked the project for “something like wp-playground but for Joomla”, and WordPress users have had three such tools for years.

The good news is that picking is not a one-time decision. You can open a Joomla 5.4 test site or a Joomla 6.1 test site in one click, then switch the next time you need the other. For the full menu of ways to get a test environment, including local stacks and the official trial, see the pillar guide on the free Joomla test site.

Conclusion

Three things separate the two lines: PHP requirements, automatic updates, and how long each is supported. Joomla 5’s regular support ends 13 October 2026 and Joomla 6’s runs to 17 October 2028, which is the difference that should drive your decision. In September 2026 the current packages are 6.1.3 and 5.4.8, and Joomla 6.2 arrives the same day Joomla 5 goes security-only.

Test on the version your live site actually runs, and start getting familiar with 6.1 if you have not already. It is the line with the longer runway. You can spin up a test site on either version in one click and let it delete itself when you are done.

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