Visiting the Nitecore web site I note that the TM11 and TM15 have apparently received upgrades to their LEDs and output levels. Both are now listed as with XM-L2 Leds and the TM11 is now listed as 2500 Lumens output, up from 2000, while the TM15 is now upgraded from 2450 Lumens to 2650. I have not yet found a dealer listing the new lights other than Battery Junction having the new TM15 but presumably they will be available shortly.
I would think Illumination supply will get them as well
Further checking found that Longhorn Tactical has both the new higher output versions listed though their listings are not fully updated yet.
The upgrade was announced a while ago, but most dealers have existing inventory and haven't sold out of them yet.
CalvinS;
Any idea when you will be getting the new ones in?
No real estimate, we have too many of the old models and we can't discount them directly so it's hard to get rid of them.
Time for a group buy? 
!!!
Calvin’s given some really generous discounts in the past on those lights but i just didn’t have the budget for it. Generous being a good 20% below whatever cheapest price was already out there! Wish I could afford!