What is the correct/official/proper/recommended way of accomplishing drag/drop in tkinter? My documentation section 24.1.1 includes:

Tkdnd Drag-and-drop support for Tkinter. This is experimental and
  should become deprecated when it is replaced with the Tk DND.

but I can find no other official documentation. Does Tkinter have drag/drop support at all? Is this something version dependant? Is this something not yet included in tk(tcl) which will then filter through to tkinter?
I should stress that I am talking about drag/drop between different applications and that I am currently using python 2 (although any solution which relies on python 3 would still be of interest).
Tkinter has no built-in support for dragging and dropping between applications. Tkdnd is, AFAIK, the only way to accomplish it without writing the low level code yourself.
Drag and Drop in Tkinter?