At the moment, we don’t support custom post type yet. But if you want to achieve that, you may need to do a custom change. I will help you to add support for custom post type but I can’t promise it will work fine on the custom post type. Please go to this file wp-content/plugins/epic-split-post/includes/class/class-sp.php, please replace this code get_post_type() === 'post' with the commented out code here. Also, please go to this file wp-content/plugins/epic-split-post/includes/class/class-sp-meta-box.php, please replace 'post' with the commented out code here. Let us know if you have further question.