Well, honestly: What do you expect? How could a book, that was written about 1980, give you today "the latest update on cosmos, science and universe"? How should Sagan have known, he was a serious scientist and not Nostradamus. If you want the latest news of science, simply choose a newer book!
Much more interesting is, that the scientific facts given in the book are nearly all still correct after all this time. What Sagan says about our possibility of self destruction or climatic changes on earth due to human influence is even more important than it was 30 years ago. I reread some passages last year again (I read the first German edition in the 1980s) and was astonished, how up to date the book and the message within still is.