The Marshmellow update became available a few days ago. I have the Blu Vivo XL which i updated it today through the "wireless update" in the menu. I actually didn't know it was waiting on me.
If that's the case, they better release the Life One X update already. Both these phones are based on the same Mediatek MT6753 CPU, so there's little reason to keep us L1X users waiting. That said I'm happy at least VXL users got it.