Dolibarr: PHP installation does not support Intl functions

The Dolibarr installer says PHP does not support Intl. It is only a warning: what really depends on it, and how to enable the extension on your server.

On the installer’s prerequisites page, one line is in orange:

Your PHP installation does not support functions Intl.

In versions 19 and 22, the wording is Your PHP installation does not support Intl functions.

It is only a warning

The installer carries on: on the test instance, without the extension, the page buttons stayed available. In the code, this check is explicitly non-blocking, like the ones for GD, Curl or ZIP.

So Dolibarr works without intl. Two core functions use it and fall back to a degraded mode when it is missing:

guessing a language from a country, when the pair is not obvious. It is used among other things for the default language choice and for the public payment pages;
checking that an email domain has a mail server (MX record). This check goes through idn_to_ascii, an intl function: without the extension, it does not run.

Nothing serious, but no reason to go without it either: the extension installs in one command.

Enabling it on Debian or Ubuntu

sudo apt install php-intl
sudo systemctl restart apache2

The php-intl package installs the version matching the system’s default PHP: php8.2-intl on Debian 12, php8.3-intl on Ubuntu 24.04. If your server uses another PHP version, install the package for that version (php8.1-intl, for example).

If PHP runs as PHP-FPM rather than inside Apache, restart that service instead, for example sudo systemctl restart php8.2-fpm.

On Windows (XAMPP, WAMP, manual install)

Open the php.ini used by your web server. In the template shipped with PHP 8, the line is already there, commented out:

;extension=intl

Remove the semicolon, save, then restart Apache.

In Docker

The official dolibarr/dolibarr image already includes the extension: checked on 24.0.1. If you see this message in a container, the image is not the official one.

On shared hosting

You do not control PHP. Most hosts offer a page in their control panel to set the PHP version and its extensions. If intl is not listed, ask their support.

Checking that it is fixed

Reload the installer’s check page: “Intl” now appears in the line “This PHP supports … functions”. If Dolibarr is already installed, the same information is under Admin ToolsAbout PHP.

Be careful with php -m on the command line: the PHP in your terminal is not necessarily the one used by the web server, nor configured with the same php.ini.

“Your PHP installation does not support functions Intl”