With so many cross-generation games launching this year, both Sony and Microsoft have announced plans to let gamers "upgrade" from one gen to the next--usually at a cost of about $10. However, there isn't just one way to take advantage of this deal. As Call of Duty: Ghosts proves, there are many ways to upgrade to the Xbox One and PS4 version of the game.

For example, there will be a disc-less "Game Ahead" version of Call of Duty: Ghosts you can purchase at participating retailers. For $69.99, this version will include digital versions of the Xbox 360 and Xbox One version of the game. When redeemed, both games will be tied to a single Gamertag.

Ghosts will also be available digitally on Xbox Live Marketplace on day one--a first for the Xbox Live service. By buying the game on Xbox Live, you'll be automatically be able to buy the Xbox One version when it launches for $10. PlayStation Network will offer the same functionality, as well.

PS3 owners that prefer buying things at retail won't have to buy a special version of the game. Instead, they will find a voucher in every new physical copy of the game. With that code, you'll be able to download the PS4 version of the game from the PlayStation Store for $10.

There's even more ways of upgrading from one version to the next, depending largely on what retailer you buy the game from. For more info, you'll want to check out the official Call of Duty website.