manodrum - Sorry for the delayed response, somehow I missed your post.
We currently don't expose song release year yet. It is coming soon. Until then, filtering by song_hotttnesss is the best way to go. We also have some pseudo-genres that you can use to get current music. Here's an example call:
http://developer.echonest.com/api/v4/playlist/static?api_key=your_api_key&results=100&type=genre-radio&genre=current
-- Paul