Is my Joomla site ready for Joomla 6?

In the site administration, whose address ends with /administrator. On Joomla 3, the version shows at the bottom of the page; on Joomla 4, 5 and 6, open System, then System Information, which also gives the PHP and database versions. Without access, this tool reads it in the public files of the site, when they are not blocked.

Because the site blocks the public files that carry the version number, with a security extension or a server rule. It is good practice: the version is then read in the administration, System, then System Information.

No. The official path goes through 3.10, then 4.4, then 5.4, then Joomla 6, with the pre-update check each time. On a test copy, the steps can follow one another in the same day. When the template and extensions are too old, rebuilding the site on Joomla 6 while keeping its texts and addresses is sometimes less work.

Yes, until 12 October 2027, provided you are on the latest 5.4 and on a PHP version that still gets fixes. As Joomla 6 requires PHP 8.3 and PHP 8.2 stops on 31 December 2026, doing both updates together makes sense.

Because it has had no security fixes since 17 August 2023, or since 17 February 2025 with the paid extended support, and it usually runs on a PHP version that has no fixes either. A site that displays is not a protected site: a flaw found today will never be fixed.

Cassiopeia, the template shipped with Joomla, follows the updates. A bought template (Helix Ultimate, YOOtheme Pro…) moves over if its publisher has released a Joomla 6 version: install it first. A custom-made template gets tried on a copy: it may need some fixes, sometimes a full rework, without changing how the site looks.

For PHP and the database, yes: the switch is made in their client area. For Joomla, the template and the extensions, no: that is up to you, the agency that built the site, or a developer who knows Joomla.

It depends mostly on the template and the extensions. With me, a simple version upgrade costs €190 (backup, test on a copy, Joomla 6 and PHP 8.3, written report), and €390 when a custom-made template also has to be adapted or extensions replaced. For a Joomla 3 site, the price is given after a free diagnosis.

It reads the home page once, as a browser would, then at most five small public files: the version file of the Joomla core, three language files when that one is blocked, and the administration login page for the PHP version, when the server shows it. It recognises Joomla, its version, the template and the extensions loaded by the home page. It logs in to nothing, tries no password and keeps the result ten minutes in cache. It cannot see extensions that load nothing on the home page, nor the database version, nor changes made to the template: only a check from the inside settles it.