It will be added to the GUI in 14.2, plus if all works out as planned we'll even add DFT-D3.
However, you don't need to use the customized script anymore (since 13.8.0) - it's built into the "NanoLanguage" module. So, you can just use DFT-D2 as in the attached example.
And - from that example you will see that optimization already is supported, and it has been all the time. In fact, it's the whole point of the D2 potential. (Stress was not included in the prototype, but it is now, in 13.8.0.)
The only final point to make is that the method is slow in 13.8.0, but this will also be considered in 14.2.
