WPML 4.5 - Fatal error: Uncaught Error: Undefined constant "WPML_TM_VERSION"

Overview of the issue

If you have a Multilingual Blog license and you have recently upgraded to WPML 4.5.0 or you migrate your site to a new URL that uses a Blog license, you may find the following error when you go to WPML → Languages → Edit Languages:

Fatal error: Uncaught Error: Undefined constant “WPML_TM_VERSION” in …/wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/tm/classes/ATE/API/class-wpml-tm-ate-authentication.php:109

Workaround

We are working on a fix and will release it soon. In the meantime, follow the steps below as a workaround.

Please, be sure to make a full backup before proceeding.

1. Open /wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/tm/classes/ATE/API/class-wpml-tm-ate-authentication.php.
2. Look for line 109.
3. Replace:

   		$query['wpml_tm_version']   = WPML_TM_VERSION;
   

4. With:

   		if (!defined("WPML_TM_VERSION")) {
   			define( 'WPML_TM_VERSION', '2.11.0' );
   		}
   		$query['wpml_tm_version']   = WPML_TM_VERSION;