It really depends on the actual content. If it looks like a blog, it's better to keep the date and it will also make sense to continue posting from time to time. If you want it to be more of a static informational site, maybe you could hide the date, but the the content still needs to look legit and trustworthy. Having the current year somewhere in the content might make it look fresh. If you want to be sneaky, I'm sure you can find a way to display the current year dynamically somewhere inside your content so the content itself will always sound current, because the year mentioned will always be the current year.