Parse error: syntax error, unexpected 'if' (T_IF)

Bonjour

j'ai cette erreur :

Parse error: syntax error, unexpected 'if' (T_IF) in /htdocs/wp-content/plugins/cs-framework/include/post-types/campaigns.php on line 1

voici mon code ; un coup de pouce. merci

<?php
/**
 * @Manage Columns
 * @return
 *
 */
 
if (!class_exists('post_type_campaign')) {

    class post_type_campaign {

        // The Constructor
        public function __construct() {
            // Adding columns
            add_filter('manage_campaigns_posts_columns', array(&$this, 'cs_campaigns_columns_add'));
            add_action('manage_campaigns_posts_custom_column', array(&$this, 'cs_campaigns_columns'), 10, 2);
   add_action('init', array(&$this, 'cs_campaigns_register'));
   add_action('init', array(&$this, 'cs_port_cat_register'));
        }
  
  function cs_campaigns_columns_add($columns) {
   $columns['category'] =__('Categories','cs_frame');
   return $columns;
  }

  function cs_campaigns_columns($name) {
   global $post;
   switch ($name) {
    case 'category':
     $categories = get_the_terms( $post->ID, 'campaign-category' );
      if($categories <> ""){
       $couter_comma = 0;
       foreach ( $categories as $category ) {
        echo esc_attr($category->name);
        $couter_comma++;
        if ( $couter_comma < count($categories) ) {
         echo ", ";
        }
       }
      }
     break;
   }
  }
  
  
  /**
   * @Register Post Type
   * @return
   *
   */
  function cs_campaigns_register() {
   $labels = array(
    'name' =>__('Campaigns','cs_frame'),
    'all_items' =>__('Campaigns','cs_frame'),
    'add_new_item' =>__('Add New Campaign','cs_frame'), 
    'edit_item' =>__('Edit Campaign','cs_frame'), 
    'new_item' =>__('New Campaign Item','cs_frame'),
    'add_new' =>__('Add New Campaign','cs_frame'),
    'view_item' =>__('View Campaign Item','cs_frame'), 
    'search_items' =>__('Search Campaign','cs_frame'), 
    'not_found' =>__('Nothing found','cs_frame'),  
    'not_found_in_trash' =>__('Nothing found in Trash','cs_frame'),
    'parent_item_colon' => ''
   );
   
   $args = array(
    'labels' => $labels,
    'public' => true,
    'publicly_queryable' => true,
    'show_ui' => true,
    'query_var' => true,
    'menu_icon' => 'dashicons-book',
    'rewrite' => true,
    'capability_type' => 'post',
    'has_archive' => true,
    'map_meta_cap' => true,
    'hierarchical' => false,
    'menu_position' => null,
    'can_export' => true,
    'supports' => array('title','editor','thumbnail')
   ); 
   register_post_type( 'campaigns' , $args );
  }
  
  /**
   * @Register Categories
   * @return
   *
   */ 
  function cs_port_cat_register() {
   $labels = array(
    'name' =>__('Campaign Categories','cs_frame'), 
    'search_items' =>__('Search Campaign Categories','cs_frame'), 
    'edit_item' =>__('Edit Campaign Category','cs_frame'), 
    'update_item' =>__('Update Campaign Category','cs_frame'), 
    'add_new_item' =>__('Add New Category','cs_frame'), 
    'menu_name' =>__('Categories','cs_frame'), 
   );  
   register_taxonomy('campaign-category',array('campaigns'), array(
    'hierarchical' => true,
    'labels' => $labels,
    'show_ui' => true,
    'query_var' => true,
    'rewrite' => array('slug' => 'campaign-category'),
   ));
  }
 }
 
 return new post_type_campaign();
}

Est ce une erreur de version php?
sur mon hébergeur il recommande php7
mais je travaille avec xampp et je pense php 5.3
Si c'est cela, comment faire evoluer ce code? merci