好的-这里有一个方法-感谢@Rarst为我指明了正确的方向。

如果找不到plugins\\u api函数，请包含require文件：

if ( ! function_exists( \'plugins_api\' ) ) {
      require_once( ABSPATH . \'wp-admin/includes/plugin-install.php\' );
}

// set the arguments to get latest info from repository via API ##
$args = array(
    \'slug\' => \'plugin-slug-name\',
    \'fields\' => array(
        \'version\' => true,
    )
);

/** Prepare our query */
$call_api = plugins_api( \'plugin_information\', $args );

/** Check for Errors & Display the results */
if ( is_wp_error( $call_api ) ) {

    $api_error = $call_api->get_error_message();

} else {

    //echo $call_api; // everything ##

    if ( ! empty( $call_api->version ) ) {

        $version_latest = $call_api->version;

    }

}