In a candid statement on the DayZ blog, the team admits that the game will only reach its beta phase of development sometime in late 2014, hence a release in 2015.
The DayZ Alpha is available for early adopters from Steam for 23.99 Euros. Please be aware that our Early Access offer is a representation of our core pillars, and the framework we have created around them. It’s a work in progress and therefore contains a variety of bugs. We strongly advise you not to buy and play the game at this stage unless you clearly understand what Early Access means and are interested in participating in the ongoing development cycle. Please keep in mind that we do not expect to reach Beta status sooner than the end of 2014.
Read the full post and get a hint as to what the team will be working on next on the DayZ site.