Far Cry 4 Complete Edition will be available in June 2015, bringing together the massive main game with all of its DLC to date into one very nice package indeed.
The original press release indicated that June date for the release of the PS4 and PC versions of the complete edition, with no mention of Xbox One. At the time, we thought that meant Microsoft's console would be getting it at a later date but it seems that isn't the case.
The folk at Gamereactor reached out to publishers Ubisoft for an update on the Xbox One version of the collection and got these words back in reply:
"The Far Cry 4 Complete Edition will be released on June 19, 2015 on Playstation4 and PC only in EMEA territories. We have no plans to release it on Xbox One"
You don't much more definitive than that and with no more information to go on, we'll probably never know why this version won't be making it to Xbox One.
That said, the base game has been out since lae 2014 and the Season Pass entitles you to all the content which will come in the complete edition. Shop around and you should be able to get both for a decent price, meaning those Yeti's are still available to Xbox One users.
The Far Cry 4 complete edition comes to PS4 and PC on the 19th of June 2015.