Wordpress : Disable Gutenberg

// Disable Gutenberg

if (version_compare($GLOBALS['wp_version'], '5.0-beta', '>')) {

    // WP > 5 beta
    add_filter('use_block_editor_for_post_type', '__return_false', 10);

} else {

    // WP < 5 beta
    add_filter('gutenberg_can_edit_post_type', '__return_false', 10);

}