In cases where several versions of php are installed on the server for different projects and you need to run composer using a specific version of php, use the following examples:

1. For example, for php 7.3

php7.3 -f /usr/local/bin/composer update

2. For example, for php 8.1

php8.1 -f /usr/local/bin/composer update

The versions indicated in the examples must be installed on the server; this command specifies which version of php should be used to execute the update command.