Okay, let me desribe in more detail how I did this:
On the Online Chess hub (where one's ongoing games are shown), there's a link at the right that says "Start New Game". When you click on this, it takes you to a page that says "Create New Online Game", and then it has two pull-down menus, the first is to select the usual options, the second is if you want a specific player. It says it will pick a random opponent with "... [sic] rating between [rating x] and [rating y]". Ratings x and y were 300 less and more than my current rating. So I hit "Create New Game". But I wasn't paired with a random opponent between those ratings; I was paired with an unrated player.
Sorry, I'm new to the site, but apparently it just changed before I joined, so it's new to everyone. I don't know what filter you're talking about other than the one I mentioned.
I just started playing here about a week ago. Tonight, I tried to create a new online game with a "ratings filter" within 300 points of my own rating. I was matched with an unrated player. I would rather not play unrated players, but aborting counts negatively against you. Is this just a bug in the new software, or am I not understanding the option correctly? Thanks.