How to implement active: 'selector:last' in 10x?

How to implement active: 'selector:last' in 10x?

If I understand correctly, looks like this is no longer valid for 1.10.x (and I can confirm doesn't work for me, though works fine with legacy 1.9):

  2. $(document).ready(function(){
  3.             $('#accordion').accordion({
  4. active: 'h2:last'
  5.             });
  6.         }); 
What is equivalent for 1.10.x? I can't really do integer (which does work) without kludgy hoop-jumping since content will be loaded dynamically from CMS and number of entries will change often.