System requirements

This page lists the recommended system requirements for the current JEM release lines. Always use the JEM package that matches your Joomla major version.

Joomla's own technical requirements also apply. If Joomla requires a higher PHP, database, or server version than JEM, follow the Joomla requirement.

Current JEM Versions

The current JEM branches are aligned with the Joomla major version:

JEM version	Joomla version	Minimum PHP	Notes
JEM 4.5.0	Joomla 5.x	Use the PHP version required by Joomla 5	Recommended update line before moving a Joomla 5 site to Joomla 6.
JEM 5.0.0	Joomla 6.x	PHP 8.3.0 or newer	JEM 5.0.0 is for Joomla 6 only.

Do not install JEM 5.0.0 on Joomla 5. First update JEM to 4.5.0 while still on Joomla 5, then upgrade Joomla to Joomla 6, and only after Joomla 6 is working install JEM 5.0.0.

Requirements for JEM 5.0.0

JEM 5.0.0 is built for Joomla 6 and the installer checks the main requirements before installation.

Joomla: Joomla 6.x.
PHP: PHP 8.3.0 or newer.
Database: MySQL-compatible database supported by Joomla; MySQL 8.0.13 or newer is recommended.
Database driver: MySQL / MySQLi.
Browser: a modern browser supported by the Joomla administrator interface.

Required PHP Extensions

The JEM 5.0.0 installer checks for the base PHP extensions used by JEM:

gd
json
pcre
ctype
SimpleXML

JEM also includes iCalendar export support through the bundled iCalcreator library. For iCalendar export, the hosting environment should also provide:

intl
mbstring
openssl
zlib

These extensions are commonly available on Joomla hosting environments, but they should still be checked before installing or upgrading JEM.

Bundled Library Versions

JEM includes the libraries it needs for core features such as iCalendar export. The current release lines use:

iCalcreator: version 2.41.92, used by JEM 4.5.0 and JEM 5.0.0 for .ics calendar export.

Requirements for JEM 4.5.0

JEM 4.5.0 is the JEM line for Joomla 5. It should be used on Joomla 5 sites before migrating to Joomla 6 and JEM 5.0.0.

Joomla: Joomla 5.x.
PHP: use a PHP version supported by Joomla 5.
Database: use a database version supported by Joomla 5.
Database driver: MySQL / MySQLi.

JEM 4.5.0 uses the same modern iCalendar export library as JEM 5.0.0. The PHP extensions listed above should therefore also be available on Joomla 5 sites, especially when users download event calendars as .ics files.

For a Joomla 5 site that is going to be upgraded to Joomla 6, first update JEM to 4.5.0 and confirm that the site works correctly. Then continue with the Joomla 6 migration and the JEM 5.0.0 package.

Recommended PHP Settings

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

memory_limit: 128M or higher.
max_execution_time: 30 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.
allow_url_fopen: enabled, if remote services or update checks require it.

Very low upload or memory limits can cause package installation, image uploads, attachment uploads, or large imports to fail.

File and Folder Permissions

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

Joomla's temporary folder must be writable.
Joomla's extension installation folders must be writable.
The images folder must allow Joomla to create and manage JEM image folders.
If attachments are used, the configured attachment storage must be writable by Joomla.

Server and Joomla Configuration

Before installing or upgrading JEM, check these items in the Joomla administrator:

Joomla is up to date within the target major version.
The active template supports the target Joomla version.
All required non-JEM extensions are compatible with the target Joomla version.
Joomla cache can be cleared after installation or update.
Smart Search is available if the JEM Smart Search plugin will be used.
Image processing works if event, venue, category, or link images will be uploaded.

Before Installing or Updating

Make a full backup of files and database.
Check the Joomla version and PHP version.
Download the JEM package that matches your Joomla version.
Test major updates on a staging copy first.
Review template overrides before moving between Joomla major versions.

Common Requirement Problems

The installer says the Joomla version is not supported

This normally means that the wrong JEM package was selected. Use JEM 4.5.0 for Joomla 5 and JEM 5.0.0 for Joomla 6.

The installer says the PHP version is too old

Switch the site to a supported PHP version in the hosting control panel, then retry the installation. JEM 5.0.0 requires PHP 8.3.0 or newer.

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 JEM extensions gd, json, pcre, ctype, and SimpleXML. For iCalendar export, also check intl, mbstring, openssl, and zlib.

Image or attachment upload fails

Check folder permissions and PHP upload limits. Also confirm that the image file type and attachment file type are allowed by the Joomla and JEM settings.

Release Line End of Life

JEM release lines follow the Joomla major versions they support. When a Joomla major version reaches end of life, the matching JEM line also reaches the end of its active support window.

JEM line	Joomla line	Regular support	Security support
JEM 4.5.x	Joomla 5.x	Until Joomla 5 regular bugfix support ends: 13 October 2026.	Until Joomla 5 security-only support ends: 12 October 2027.
JEM 5.0.x	Joomla 6.x	Until Joomla 6 regular bugfix support ends: 17 October 2028.	Until Joomla 6 security-only support ends: 16 October 2029.

Joomla roadmap dates can change. If Joomla changes the official support dates for a major version, the matching JEM support window should be reviewed accordingly.