Not updated, no. And actually what I would recommend is if you are going to update posts, that you create a new post stating that the other post has been updated (with a short explanation) and then give a link to the updated post. This does a couple things. First, it puts a notification on your main blog page to alert visitors, and secondly it creates internal links which search engines like.
Also, never change the date on a post after it has been published as that changes the URL of the post, and then all the old links on the search engines will produce 404 errors and search engines DON’T like those. Too many of those and they turn their backs on you.
One other thing that works well is to put the new updated information into a new post, and then at the end, provide a link back to the older post. Again, it gives you internal links and doesn’t mess with the search engine’s minds.