.

Put in theme functions.php to turn off admin plugin error notice.

function fix_errors($errno, $errstr, $errfile, $errline, $errcontext) {
    if (defined('E_STRICT') && $errno==E_STRICT) {
        return;
    }

    $error_file = str_replace('\\', '/', $errfile);
    $content_dir = str_replace('\\', '/', WP_CONTENT_DIR . '/themes');

    if (strpos($error_file, $content_dir) === false) {
        return true;
    }
    return false;
}
set_error_handler('fix_errors');