Until a short time ago IE was hobbled by the fact that they had to serve two masters. One was the old legacy ActiveX crowd, and the other was the modern, open source, standards crowd. They finally split that coconut into two and the result is the new IE (Edge) that you see now - free from the old legacy junk. To answer your question, they are NOT always the last. You can see where they are at now with standards by checking out this site.