I disagree, for instance, here's a (IMO) exact description of the K&R 'relevance':

"It's not even a very good way to learn C. The idioms and best-practices for C programming have evolved substantially, even since the second edition was published, and some of the code samples look a bit dated." And this is from 2004, meaning it got even more dated.(http://sites.google.com/site/steveyegge2/ten-great-books)

The reason K&R is still the canonical C book is because it represents the language better than any other book, before or since, not because the language stagnated since ANSI C was created.