Title: WordPress 4.9 compatability
Last modified: April 23, 2021

---

# WordPress 4.9 compatability

 *  Resolved [Viktor Nagornyy](https://wordpress.org/support/users/viktorix/)
 * (@viktorix)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/)
 * The plugin’s page says AMP plugin is compatible with v4.9 but it doesn’t work.
   It throws an error looking for i18n, which was added for Gutenberg. Do you plan
   to maintain compatibility with v4.9 or is the compatibility tag wrong? Maintaining
   compatibility with v4.9 also ensures the plugin works with the ClassicPress fork,
   which is where I noticed this issue.
 * A team member from Beaver Builder [shared a polyfill](https://forums.classicpress.net/t/amp-plugin-for-wordpress-issues/3125/5?u=viktor)
   that fixes this issue for now. I’m sharing it for reference in case someone else
   needs it:
 * Check and enqueue script:
 *     ```
       if ( ! wp_script_is( 'wp-i18n', 'registered' ) ) {
       			wp_enqueue_script( 'fl-wp-i18n', "{$js_vendors}i18n-polyfill.js" );
       		}
       ```
   
 * JavaScript file:
 *     ```
       window.wp = window.wp || {};
       window.wp.i18n = {};
       ```
   
 * Thanks.

Viewing 8 replies - 1 through 8 (of 8 total)

 *  Plugin Author [Weston Ruter](https://wordpress.org/support/users/westonruter/)
 * (@westonruter)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14357434)
 * It is supposed to work in 4.9 still, although some functionality is disabled 
   since it requires 5.3 and above. We’ll look into fixing compatibility with 4.9
   so that no error is emitted.
 *  Plugin Author [Weston Ruter](https://wordpress.org/support/users/westonruter/)
 * (@westonruter)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14357449)
 * [@viktorix](https://wordpress.org/support/users/viktorix/) What version of Gutenberg
   are you running on 4.9? You have to be running an old version since the current
   version requires a more recent version of WP. Or is this error appearing on the
   classic editor screen? Or actually, from the link you shared the issue is specifically
   showing up on the AMP settings screen? Please confirm which screens which include
   this error.
 *  Plugin Support [Milind More](https://wordpress.org/support/users/milindmore22/)
 * (@milindmore22)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14357566)
 * Hello [@westonruter](https://wordpress.org/support/users/westonruter/)
 * I can confirm this on the AMP settings screen with WP 4.9
 *     ```
       Uncaught TypeError: Cannot read property 'i18n' of undefined
           at wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1
           at Object.2 (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at r (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at Object.48 (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at r (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at Module.<anonymous> (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at Module.216 (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at r (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at Object.215 (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
           at r (wp-api-fetch.js?ver=7645fa7ef83c5d94141bdac792ab796a:1)
       admin.php?page=amp-options:81 
   
       Uncaught ReferenceError: wp is not defined
           at admin.php?page=amp-options:81
       ```
   
 *  Plugin Support [Milind More](https://wordpress.org/support/users/milindmore22/)
 * (@milindmore22)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14357668)
 * Hello [@viktorix](https://wordpress.org/support/users/viktorix/)
 * I have filed [an issue](https://github.com/ampproject/amp-wp/issues/6100) for
   the same, please subscribe to issue to get updates.
 *  [marktdavenport](https://wordpress.org/support/users/marktdavenport/)
 * (@marktdavenport)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14357680)
 * [@westonruter](https://wordpress.org/support/users/westonruter/) The reason for
   using WP 4.9 or ClassicPress is that there is no Gutenberg at all, any version.
 *  Thread Starter [Viktor Nagornyy](https://wordpress.org/support/users/viktorix/)
 * (@viktorix)
 * [5 years, 1 month ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14358088)
 * [@milindmore22](https://wordpress.org/support/users/milindmore22/) thanks, I 
   appreciate this.
 *  Plugin Support [Milind More](https://wordpress.org/support/users/milindmore22/)
 * (@milindmore22)
 * [5 years ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14489822)
 * Hello [@viktorix](https://wordpress.org/support/users/viktorix/) and [@marktdavenport](https://wordpress.org/support/users/marktdavenport/)
 * JFI : We have merged [a fix](https://github.com/ampproject/amp-wp/pull/6119) 
   in v2.1 feel free update plugin to latest version let us know if you have any
   feedback.
 *  Plugin Support [Milind More](https://wordpress.org/support/users/milindmore22/)
 * (@milindmore22)
 * [5 years ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14527992)
 * As we didn’t receive a response I’ll mark this as resolved. Feel free to open
   a [new support topic](https://wordpress.org/support/plugin/amp/#new-post) if 
   you require any further assistance.

Viewing 8 replies - 1 through 8 (of 8 total)

The topic ‘WordPress 4.9 compatability’ is closed to new replies.

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## Tags

 * [i18n](https://wordpress.org/support/topic-tag/i18n/)

 * 8 replies
 * 4 participants
 * Last reply from: [Milind More](https://wordpress.org/support/users/milindmore22/)
 * Last activity: [5 years ago](https://wordpress.org/support/topic/wordpress-4-9-compatability-2/#post-14527992)
 * Status: resolved