As far as I can tell there aren't really any hints this time around. It makes sense, though - 4.0 is still very fresh and 4.1 is due to release in about a month...give or take. Development on 5.0 may very well have started but it's likely still up in the air as to what exactly it will entail - so hints as to what it will contain probably won't show up until next year's anniversary event.