Since I've (more or less) taken over the header translation of NGD to delphi, you can always get the newest header version at http://newton.delphigl.de.

Since I haven't had the time to update the headers to 1.31 you'll have to wait (had to work today ) a bit, but I'll start updating the beta-header (which is already 1.31) right now and let you know when it's finally available.

And since I'm on the SDK-Developer team for newton, I already was using 1.31 for several weeks now and can only say that newton gets better and better. Expecially the new possibility of choosing between three solver models is a great feature.

Update :
I just did a Diff between the beta-SD-Header and the header for final 1.31 relase and there were no differences, so not much work to do.
You can now get the updated header at the above mentioned page.