To be precise, Node.js 6.x will include V8 5.0. There has been a little discussion on being able to include V8 5.1 down the road, maybe, but there is nothing concrete on it at this point.<p>Also, the fate for tail-call-elimination is pretty uncertain at the moment; see: <a href="https:&#x2F;&#x2F;github.com&#x2F;tc39&#x2F;proposal-ptc-syntax" rel="nofollow">https:&#x2F;&#x2F;github.com&#x2F;tc39&#x2F;proposal-ptc-syntax</a>