You can set the PHP version in vvv-custom.yml when defining a site. To do this, use the nginx_upstream option to specify the PHP version. VVV also needs to be told to install that version of PHP using the utilities section.

Here’s an example that uses PHP v7.1:

sites:
  example:
    nginx_upstream: php71

utilities:
  core:
    - php71

This will not work if set $upstream {upstream}; is removed from the nginx config.

In this example, we have changed the wordpress-default site to use PHP 7.1, and the wordpress-develop site to use PHP 5.6:

sites:
  wordpress-default:
    repo: https://github.com/Varying-Vagrant-Vagrants/vvv-wordpress-default.git
    nginx_upstream: php71
    hosts:
      - local.wordpress.dev

  wordpress-develop:
    repo: https://github.com/Varying-Vagrant-Vagrants/vvv-wordpress-develop.git
    nginx_upstream: php56
    hosts:
      - src.wordpress-develop.dev
      - build.wordpress-develop.dev

utilities:
  core:
    - memcached-admin
    - opcache-status
    - phpmyadmin
    - webgrind
    - php56
    - php71

Forcing a Version of PHP

It may be desirable to force a site to use a particular version of PHP, even if vvv-custom.yml disagrees.

This is done by overriding the nginx upstream value inside vvv-nginx.conf. To do this change this:

 set $upstream {upstream};

To this:

 set $upstream php71;

That site is now using PHP 7.1, remember to reprovision using vagrant reload --provision