New version of Macbook Pro
No-one really knows for certain when Apple are going to release new hardware except for Apple. So any answer is likely to be opinion-based which might get your question deleted.

That said, some sites online try to give an informed guess by analysing previous release schedules. For example, MacRumors who currently recommend against buying a Macbook Pro as they believe a new release is imminent.

http://buyersguide.macrumors.com/#Retina_MacBook_Pro

But like I said, this is just guesswork.