Init.php

// Check dependencies
include_once(ABSPATH . 'wp-admin/includes/plugin.php');
if (!is_plugin_active('gravityforms/gravityforms.php')) {
  add_action('admin_notices', function() {
      echo '<div class="error"><p>This plugin requires the Gravity Forms plugin to be enabled, and is not currently running.</p></div>';
    });

  if (class_exists('Burst')) {
    Burst::log("Gravity Forms dependency unmet.", BURST_CRITICAL);
  }

  // Skip loading the rest of the plugin, dependency check failed.
  return;
}