I recently pull up from under ten inches of dust one of my agile book. The book is now six years old; published in 2008. I prefer to keep it anonymous preventing to create a guerrilla of which one will yielded the best book about this subject. For that, I'm totally able to do a simple search from Amazon or Gooble to find the best book.

I seen a couple of books about agile released in the last 2-3 years and I'm wondering if it will be a good investment to buy a more recent book than my old one.

I mean, is there any great advancements in the last few years in the world of agile that worth to buy a more recent book?

Thank you.