Unable to update PHP dependencies via PHP Composer in Plesk: Support for composer 1 is deprecated

Julian Bonpland Mignaquy

Updated January 13, 2026 19:07

kb: bug Plesk for Windows Plesk for Linux

Applicable to:

Unable to update PHP dependencies via PHP Composer in Plesk:

PLESK_ERROR: Support for composer 1 is deprecated

Currently, Plesk is using Composer 1 by default. This behavior is planned to be changed in future extension updates in scope of EXTPHPCOMP-188.

As a workaround, update Composer to version 2:

Click on a section to expand

Plesk on Linux

Log in to Plesk
Go to Extensions > search panel.ini editor > click Get it free
Go to Extensions > My Extensions > Panel.ini editor > Edit and add the following strings to the end of the file:

CONFIG_TEXT: [ext-composer]
commandInfoPluginVersion = "~1.1.0"
ComposerVersion = '2'
Go to Tools & Settings > Scheduled tasks (Cronjobs) and click Add task. Paste the following command and click Run now:

Ubuntu/Debian:

CONFIG_TEXT: /opt/plesk/php/7.4/bin/php /opt/psa/var/modules/composer/composer.phar self-update --2

CentOS/RHEL:

CONFIG_TEXT: /opt/plesk/php/7.4/bin/php /usr/local/psa/var/modules/composer/composer.phar self-update --2

Note: Use actual PHP version in the command above to update PHP composer

Plesk on Windows

Log in to Plesk
Install Panel.ini Editor extension
Go to Extensions > My Extensions > Panel.ini editor > Editor and add the following strings to the end of the file to keep version 2:

CONFIG_TEXT: [ext-composer]
commandInfoPluginVersion = "~1.1.0"
ComposerVersion = '2'
Run below command in CMD to perform an update:

C:\> "%plesk_dir%Additional\PleskPHP74\php.exe" "%plesk_dir%\var\modules\composer\composer.phar" self-update --2
To verify that version is correct execute the following command:

C:\> "%plesk_dir%Additional\PleskPHP74\php.exe" "%plesk_dir%\var\modules\composer\composer.phar" --version

Note: Use actual PHP version in the command above to update PHP composer