Number of pages in WP-dTree

I have happily been using WP-dTree for many years but I fear I now have reached the limit for the number of pages to be handled. Some sub-pages will not show and I remember I had that problem some years ago. The solution then was to increase the limit for the number of pages. So I did and everything was ok. The problem now is that I cant’t find the notes on how to do it. Can anyone help a forgetful man?