Update: Bohemia PR manager clarified the DayZ engine situation in an email, saying that the studio has been reworking the technology for the past four years. "It’s basically the reason why we are in Early Access for so long," he said. " Bohemia started a development of a new Enfusion Engine along with DayZ standalone—an engine that’s meant to empower our future games."
"The upcoming PC 0.63 Experimental update is going to introduce a sizeable chunk of these long-awaited tech changes that will have a massive influence over how DayZ plays and feels in general. So it’s definitely a huge milestone for the game itself, as big as having almost a completely new engine can be, but relaunch is perhaps not the correct word."
Culak added that the technological upgrade shouldn't impact the plan to launch the game this year. "This has been the plan all along: DayZ beta (when our 0.63 update reaches 'stable branch' on Steam) will introduce major tech changes that improve the gameplay, along with some new content and features," he said. "The road from beta to 1.0 will be mostly about polishing those, balancing everything, and doing additional smaller content drops."
"We're releasing DayZ on a new engine in a couple of weeks on PC, and it's gonna be coming to Game Preview on Xbox this year," lead producer Eugen Harton said. "That's basically our aim. I would almost say it's a reboot of DayZ on PC."
DayZ has been in Early Access on Steam since 2013, and has actually been around for much longer than that, yet it was only late last year that Bohemia committed to a full launch this year. Harton wouldn't say whether the shift to a new engine would mark the Early Access exit, although I have to think it would be kind of a strange approach to take: Transitioning to a new tech platform is the sort of thing I'd expect to cause headaches, not clear them up.
There's no sign of the impending engine change on Steam, but I've reached out to Bohemia for more information and will update if I receive a reply.