Definition from Wiktionary, the free dictionary
what's new (uncountable)
- (idiomatic) The latest developments in a particular situation or a person's life.
- We send out a newsletter to our clients every week to tell them what's new in the company.
- (idiomatic) An informal greeting asking the other person what has recently happened in their lives. A typical response might be, "Not much, you?". At times the greeting may not be literal and might just be used as a synonym for hello or what's up.
- (rhetorical question, idiomatic, sarcastic) Implies that the situation is and always has been unsatisfactory.
- You're still having problems with that idiot you employed last year? So, what's new?
informal greeting asking what has happened recently