Revert DB from Polylang 1.2 to 1.1.6

<?php
/*
Plugin Name: Revert Polylang 1.2 to 1.1.6
*/

/*
 * This plugin removes Polylang 1.2 data, keeping Polylang 1.1.6 data.
 * Read carefully the procedure to follow
 *
 * Procedure:
 *
 * Make a database backup if you did not make one before ugrading to 1.2
 * create a file revert.php and paste all this file (using a text editor such as notepad)
 * upload revert.php in wp-content/plugins
 * De-activate Polylang 1.2.x (DO NOT DELETE IT USING THE RED LINK 'delete' in Plugins table as every data would be removed)
 * activate the plugins 'Revert Polylang 1.2 to 1.1.6'
 * de-activate it
 * Delete the polylang directory in wp-content/plugins
 * download the file http://downloads.wordpress.org/plugin/polylang.1.1.6.zip
 * extract the content and upload the polylang directory in wp-content/plugins
 * activate Polylang 1.1.6
 */

add_action('init', 'pll_revert_to_old_db');

function pll_revert_to_old_db() {
    if (defined('POLYLANG_VERSION'))
        return;

    global $wpdb;

    // delete the strings translations 1.2+
    register_post_type('polylang_mo', array('rewrite' => false, 'query_var' => false));
    $ids = get_posts(array(
        'post_type'   => 'polylang_mo',
        'numberposts' => -1,
        'nopaging'    => true,
        'fields'      => 'ids',
    ));
    foreach ($ids as $id)
        wp_delete_post($id, true);

    // need to register the taxonomies
    foreach (array('language', 'term_language', 'post_translations', 'term_translations') as $taxonomy)
        register_taxonomy($taxonomy, null , array('label' => false, 'public' => false, 'query_var' => false, 'rewrite' => false));

    // delete all what is related to languages and translations
    foreach (get_terms(array('term_language', 'post_translations', 'term_translations'), array('hide_empty'=>false)) as $term) {
        $term_ids[] = (int) $term->term_id;
        $tt_ids[] = (int) $term->term_taxonomy_id;
    }

    if (!empty($term_ids)) {
        $term_ids = array_unique($term_ids);
        $wpdb->query("DELETE FROM $wpdb->terms WHERE term_id IN (" . implode(',', $term_ids) . ")");
        $wpdb->query("DELETE FROM $wpdb->term_taxonomy WHERE term_id IN (" . implode(',', $term_ids) . ")");
    }

    if (!empty($tt_ids)) {
        $tt_ids = array_unique($tt_ids);
        $wpdb->query("DELETE FROM $wpdb->term_relationships WHERE term_taxonomy_id IN (" . implode(',', $tt_ids) . ")");
    }

    $languages = get_terms('language', array('hide_empty' => 0));

    foreach($languages as $lang) {
        $description = maybe_unserialize($lang->description);
        if (is_array($description))
            wp_update_term((int) $lang->term_id, 'language', array('description' => $description['locale']));
    }

    $options = get_option('polylang');
    $options['version'] = '1.1.6';
    update_option('polylang', $options);
}