Requirements: composer 2.x should be used. Ideally, the php version being used to run the composer commands below should be the lowest allowed for every branch (php72 for 39 and 310, php73 for 311 and master). Steps: Remove vendor & composer.lock: rm -fr vendor composer.lock Clear composer caches: composer clearcache Install: composer install Verify that a new composer.lock file has been created. Verify that it's the same (using git diff ) that the included in this patch (some minor versions / dates differences are allowed). Run vendor/bin/behat --version Verify that "behat 3.8.1" is the version installed. Apart from this, automated test will tell us if everything is ok.