You do realise that this isn't the official DOSBox site but just where their forum is hosted. You also do realise that people would probably look at the date of posts over that of the copyright statement. A copyright statement is only of any use if you have legal standing to enforce something (which in this day and age of the web is probably not gonna happen too often!).

And finally who the hell cares, post a message in the appropraite forum and Snover (the site owner) will either ignore it or change the year 😀

It's the official website that says 2003 😀
http://dosbox.sourceforge.net/

It doesn't really matter, though, as a quick glance at the news at the top will tell that the development of DOSBox is still active.

I'm a donkey - didn't even think to look 😜