Today is the last day to take advantage of Activision's $10 next-gen upgrade offer for Call of Duty: Ghosts, so you best act quickly if you haven't already or you'll miss out.
As an effort to ease the transition from generation to generation, Activision launched a deal last year where if you purchased a copy of Call of Duty: Ghosts for either PS3 or Xbox 360, you could upgrade to PS4 or Xbox One for $10 instead of the full $60 sticker price.
The upgrade offer is only valid if you purchased a digital copy of the game. Whether you take advantage of the offer or not, your in-game stats will transfer from generation to generation, provided you stay within the same console family (i.e. Xbox 360 to Xbox One).
Activision is being a bit more generous with the Call of Duty: Ghosts DLC season pass. If you buy and activate your Xbox 360 or PS3 season pass no later than May 31, and purchase and activate an Xbox One or PS4 by that time, your content will be available on your new system for free.
More details about the Call of Duty: Ghosts upgrade plan is available through this extensive FAQ on the Call of Duty website.