Gravity Forms GFAddOn->minimum_requirements() usage.

gfaddon-minimum-requirements.php

array(
  // Require WordPress version 4.6.2 or higher.
  'wordpress' => array(
    'version' => '4.6.2'
  ),
  
  // Require PHP version 5.3 or higher.
  'php' => array(
    'version'    => '5.3',
    
    // Require specific PHP extensions.
    'extensions' => array(
    
      // Require cURL version 1.0 or higher.
      'curl' => array(
        'version' => '1.0'
      ),
      
      // Require any version of mbstring.
      'mbstring',
    ),
    
    // Require specific functions to be available.
    'functions' => array(
      'openssl_random_pseudo_bytes',
      'mcrypt_create_iv'
    ),
  ),
  
  // Require other add-ons to be present.
  'add-ons' => array(
  
    // Require any version of the Mailchimp add-on.
    'gravityformsmailchimp',
    
    // Require the Stripe add-on and ensure the name matches.
    'gravityformsstripe' => array(
      'name' => 'Gravity Forms Stripe Add-On'
    ),
    
    // Require the PayPal add-on version 5.0 or higher.
    'gravityformspaypal' => array(
      'version' => '5.0'
    ), 
  ),
  
  // Required plugins.
  'plugins'   => array(
  
    // Require the REST API.
    'rest-api/plugin.php',
    
    // Require Jetpack and ensure the name matches.
    'jetpack/jetpack.php' => 'Jetpack by WordPress.com',
  ),
  
  // Any additional custom requirements.
  array( $this, 'custom_requirement' ),
);