I have the new book. I bought it on amazon for £4 - postage free! A bargain.
On the subject of caffeine - for years the intake of too much has been discouraged, for lots of reasons. It is a stimulant, after all. I drink full caff coffee in the early part of the day. In the evenings I now only drink decaff. If I overdo the caffeine I can't sleep - and I already have sleep problems.
As Jim says the science changes all the time and is constantly being updated. Even with citric acid some people won't see a slowing of weight loss nor a kick-out of ketosis whereas others will, and very quickly, too.
As a very long-time vegetarian I am relieved to see extended advice offered to those who don't eat meat. It was once believed that veggies couldn't succeed with Atkins. Since I have lost ten stones and maintained that loss for some time now I know we can succeed! I do think that vegans have a tougher time, so perhaps this is not the 'diet' for them. I was vegan years back and it was just too difficult for me to get sufficient protein without overdosing on tofu, etc. This is, of course, a matter of personal choice.
I love Atkins and low-carbing in general and I wish I'd taken up this approach years sooner. Never mind, I found it in the end, and I can't see me ever going back to high carb eating as a way of life.