\d no more working in RegEx

In 2018 I developed a script which contains this regex:

var re_TmpVarName = new RegExp("(#zz)?\d+\-\d+\-\d+T\d+:\d+:\d+\.\d+Z");

to find variables named for example #zz2016-11-10T09:46:52.136Z

Now it turns out that (even in FM-15) the \d is no more working. I need to replace it by [0-9]:

main ();

function main () {
  var sName = "#zz2016-11-10T09:46:52.136Z";
//varr re_TmpVarName = new RegExp("(#zz)?\d+\-\d+\-\d+T\d+:\d+:\d+\.\d+Z");
  var re_TmpVarName = new RegExp("(#zz)?[0-9]+\-[0-9]+\-[0-9]+T[0-9]+:[0-9]+:[0-9]+\.[0-9]+Z");
  var aa = re_TmpVarName.test(sName);
  $.writeln (aa); // should be true
}

What is going on here?