I did some work a couple of years ago on updating it and even started layout for an Ebook version. Didn't finish. I haven't got much extra material unless I go more into the P.1103 and P.1125 / P.1129.
There's also additional stuff that was excluded from the original edition, but the contents was already shoehorned to fit into 64 pages, so unless we upped the page count, I couldn't really include this.