UPDATE 4.45PM GMT: There's an official press release up now. Listed improvements to State of Decay on Xbox One include 1080p resolution, new textures, new lighting and increased draw distance. There are new animations, an improved interface and some new playable characters. And a knife, you've got a default (it sounds like) knife.
Existing State of Decay owners, in addition to getting the 33 per cent discount listed below, will also unlock a new exclusive character called Gurubani. He's an Indian-American sword-wielding badass, apparently.
No specific European details were mentioned.
ORIGINAL STORY 2.45PM GMT: The Xbox One (and PC) version of State of Decay - the Year One Survival Edition - will be released 1st May. This is the pumped up 1080p version with smoother performance, more gore and included DLC.
The relative good news is that if you own the original game already, upgrading can be done with a 33 per cent discount, reports Polygon (evidently there was some kind of US showcase event). The Year One Survival Edition costs $20, so chop a third off that and you'll pay something like $13.
If you don't own the game already, you should definitely take a look. It's a sandbox zombie survival game with plenty of off-the-cuff charm. "Look past the ragged façade and you'll discover one of the finest open world games yet made," concluded Simon Parkin for Eurogamer - a hearty recommendation, especially as that "ragged façade" may no longer be there.