3.10 to 4.0
An explanation of the code changes for each version of Joomla. If you follow from the version of your current code until the version you want to support you should come across all the changes you need to make.
Updated System Requirements
Beside changed to the code base itself we also increased the minimum system requirements.
The system requirements have been updated as follows:
- PHP 7.2.5
- MySQL 5.6
- PostgreSQL 11.0
- SQL Server support has been dropped.
PHP MySQL Extension
Joomla no longer supports using PHP's ext/MySQL driver (which was removed in PHP 7.0). Joomla will automatically try to use the MySQLi extension (available since PHP 5.3) or the MySQL PDO Driver (available since PHP 5.3). Otherwise it will fail to create a database connection.
Strict mode has been enabled. The following flags are now active by default in Joomla 4 and you may have to update your database queries accordingly. This will help us with future MySQL version upgrades and also aligns more closely with Postgres to enable easier compatibility with queries in both languages.
As a consequence, Joomla 4 will only use
NULLdate defaults. The use of the invalid default date of 0000-00-00 00:00:00 in Joomla 4 has been deprecated.
PHP Postgres Extension
Joomla no longer supports using PHP's ext/pgsql driver. Joomla will automatically try to use the PostgreSQL PDO Driver (available since PHP 5.3 and Joomla 3.9). Otherwise it will fail to create a database connection with a Postgres Database.
PHP GMP Extension
This is required for using the WebAuthn Passwordless Login feature. Note the PHP GMP extension is installed by default on the majority of hosting sites. The WebAuthn Passwordless Login System Plugin is enabled by default in Joomla 4 on HTTPS sites.
PHP mcrypt Extension
Since the mcyprt extensions has been removed from PHP in Version 7.2.0 you need the
mycrypt PECL Package for using the
Joomla\CMS\Crypt\Cipher\CryptoCipher class and its alias
The support for mcrypt will be removed with Joomla! 5.0 or 6.0.