System requirements

This page lists the recommended system requirements and supported upgrade paths for the current JEM release lines.

JEM 5.0.0 is the current JEM release for both Joomla 5 and Joomla 6. JEM 4.5.0 is primarily intended as the final transitional JEM release for sites that are still running Joomla 4.4.

Current JEM Versions

Choose the Correct Upgrade Path

Site already running Joomla 5

1. Make a complete backup of the files and database.
2. Confirm that the server is running PHP 8.3 or newer.
3. Update the existing JEM installation directly to JEM 5.0.0.
4. Check the Joomla database schema and test the JEM frontend and administrator views.
5. If required, upgrade Joomla 5 to Joomla 6 after confirming that all installed extensions and the active template are compatible.

Site still running Joomla 4.4

1. Make a complete backup of the files and database.
2. Update JEM to JEM 4.5.0 while the site is still running Joomla 4.4.
3. Check the JEM database schema and test events, venues, categories, modules, plugins, menu items, and template overrides.
4. Upgrade Joomla 4.4 to Joomla 5.
5. Confirm that Joomla 5 and JEM 4.5.0 work correctly.
6. Change the server to PHP 8.3 or newer if this has not already been done.
7. Update JEM 4.5.0 to JEM 5.0.0.
8. After testing all extensions and the active template, optionally upgrade Joomla 5 to Joomla 6.

Requirements for JEM 5.0.0

JEM 5.0.0 is the current JEM release for Joomla 5 and Joomla 6. The same JEM package can remain installed when a compatible Joomla 5 site is upgraded to Joomla 6.

• Joomla: Joomla 5.x or Joomla 6.x.
• PHP: PHP 8.3.0 or newer.
• Database: a MySQL-compatible database supported by the installed Joomla version.
• MySQL: MySQL 8.0.13 or newer.
• MariaDB: use a version supported by the installed Joomla version.
• Database driver: MySQLi.
• Browser: a modern browser supported by the Joomla administrator interface.

If you have JEM 4.x:

• Upgrading from JEM 4.4.2 or JEM 4.5.0 to JEM 5.0.0 is supported.
• A direct upgrade from a JEM version older than 4.4.2 to JEM 5.0.0 is not supported and will be blocked.
• If you are using a version older than JEM 4.4.2, first upgrade to either JEM 4.4.2 or JEM 4.5.0. Verify that the website and database work correctly, and then upgrade to JEM 5.0.0.
• A fresh installation of JEM 5.0.0 is also supported.

Required PHP Extensions

The JEM installer and the Joomla environment require the following base PHP extensions:

• ctype
• dom
• gd
• json
• pcre
• SimpleXML
• zlib
• mysqlnd or the PHP MySQL driver required by Joomla

JEM also provides iCalendar export through the bundled iCalcreator library. The following PHP extensions should therefore also be available:

• intl
• mbstring
• openssl
• zlib

Bundled Library Versions

JEM includes the libraries required for core features such as iCalendar export.

• iCalcreator: version 2.41.92, used by JEM 4.5.0 and JEM 5.0.0 to generate .ics calendar files.

Requirements for JEM 4.5.0

JEM 4.5.0 is a transitional release intended primarily for users who still have a Joomla 4.4 site and need to prepare it for migration.

Although JEM 4.5.0 can also run on Joomla 5, it should not normally be selected for a new Joomla 5 installation. Joomla 5 sites should use JEM 5.0.0 whenever the server meets the PHP 8.3 requirement.

• Joomla: Joomla 4.4.x or Joomla 5.x.
• PHP: use a PHP version supported by the installed Joomla version and compatible with the other installed extensions.
• Database: use a database version supported by the installed Joomla version.
• Database driver: MySQLi.

JEM 4.5.0 uses the same modern iCalendar export library as JEM 5.0.0. The PHP extensions listed for iCalendar support should therefore also be available, especially when users download event calendars as .ics files.

Recommended PHP Settings

The exact values depend on the size of the site, the number of installed extensions, and the size of uploaded images and attachments. The following values are a reasonable starting point:

• memory_limit: 256M or higher.
• max_execution_time: 30 seconds or higher.
• max_input_time: 60 seconds or higher.
• upload_max_filesize: 8M or higher, depending on image and attachment uploads.
• post_max_size: equal to or higher than upload_max_filesize.
• max_file_uploads: sufficient for the number of files uploaded in a single operation.
• allow_url_fopen: enabled when remote services, update checks, or external resources require it.

File and Folder Permissions

Joomla must be able to install extensions and write to the media and image folders used by JEM. During installation and normal use, JEM creates or uses folders under images/jem for event, venue, category, and link images.

• Joomla's temporary folder must exist and be writable.
• Joomla's log folder must exist and be writable.
• Joomla's extension installation folders must be writable.
• The images folder must allow Joomla to create and manage the JEM image directories.
• If attachments are enabled, the configured attachment storage directory must be writable by Joomla.
• Files and directories should use the permissions recommended by the hosting provider; avoid insecure permissions such as 777.

Server and Joomla Configuration

Before installing or updating JEM, check the following items in the Joomla administrator interface:

• Joomla is up to date within the currently installed major version.
• The active administrator and site templates support the target Joomla version.
• All required third-party extensions are compatible with the target Joomla and PHP versions.
• The Joomla database schema reports no unresolved errors.
• Joomla's temporary and log folder paths are valid.
• The Joomla cache can be cleared after installation or update.
• Smart Search is enabled if the JEM Smart Search plugin will be used.
• Image processing works if event, venue, category, or link images will be uploaded.
• The Joomla Update component does not report incompatible extensions before a major Joomla upgrade.

Before Installing or Updating

• Make a full backup of the website files and database.
• Verify that the backup can be restored.
• Check the installed Joomla, JEM, PHP, and database versions.
• Download the JEM package that matches the required migration stage.
• Review all JEM-related modules and plugins.
• Test major Joomla and JEM updates on a staging copy first.
• Review template overrides before moving between Joomla major versions.
• Temporarily disable incompatible third-party plugins if required by the Joomla upgrade process.
• After updating, clear the Joomla cache and browser cache.
• Check the Joomla database schema after installation or upgrade.

Template Overrides

JEM updates and Joomla major-version upgrades may include changes to layouts, HTML structure, Bootstrap classes, helper methods, or view data.

If the site uses JEM template overrides, review the following directories before and after updating:

• templates/your-template/html/com_jem
• templates/your-template/html/mod_jem
• templates/your-template/html/mod_jem_wide
• Any other JEM module override directories under the active template.

Common Requirement Problems

The installer says that the Joomla version is not supported

Check both the Joomla version and the selected JEM package:

• Use JEM 5.0.0 on Joomla 5 or Joomla 6.
• Use JEM 4.5.0 mainly as the final JEM update on Joomla 4.4.
• Do not attempt to install JEM 5.0.0 directly on Joomla 4.

The installer says that the PHP version is too old

JEM 5.0.0 requires PHP 8.3.0 or newer. Change the PHP version through the hosting control panel and confirm that all other installed extensions support the selected PHP version before retrying the installation.

JEM 5.0.0 cannot be installed while the site is still on Joomla 4

This is expected. Update to JEM 4.5.0 on Joomla 4.4, verify the site, and then upgrade Joomla to Joomla 5. After the Joomla 5 site is working correctly and PHP 8.3 is active, update JEM to JEM 5.0.0.

The installer reports a missing PHP extension

Enable the missing extension in the hosting control panel or ask the hosting provider to enable it.

Check the base Joomla and JEM extensions, including ctype, dom, gd, json, pcre, SimpleXML, and zlib. For iCalendar export, also check intl, mbstring, and openssl.

An image or attachment upload fails

Check folder permissions, PHP memory limits, upload limits, POST limits, and execution time. Also confirm that the image or attachment file type is permitted by both the Joomla Media settings and the JEM configuration.

The site fails after changing the PHP version

A third-party extension, plugin, module, template, or template override may not support the selected PHP version. Review the Joomla error log and PHP error log, then update or disable the incompatible extension before continuing.

JEM works in the administrator but not on the frontend

Check the active site template, JEM template overrides, menu-item configuration, module assignments, access levels, and frontend error logs. Temporarily rename the JEM override directory to determine whether an outdated override is causing the problem.

Release-Line Status

Related Documentation

• Installing JEM
• Updating JEM within the same Joomla version
• Upgrading JEM and Joomla between major versions