Here's how to upgrade your current-gen games to next-gen

Gamers who received next-generation systems for the holidays still have some time to take advantage of trade-in offers allowing them to upgrade PlayStation 3 and Xbox 360 games to PlayStation 4 and Xbox One versions.

Below is a list of all next-gen upgrade offers that are still active and how to redeem them. Games included in the following the offers feature seven cross-generation multiplatform titles released this fall: Assassin's Creed 4: Black Flag, Battlefield 4, Call of Duty: Ghosts, FIFA 14, Madden NFL 25, NBA 2K14 and Need for Speed Rivals. Brawler Injustice: Gods Among Us is only part of the offer on PlayStation platforms.

Amazon

Xbox One gamers can trade in the Xbox 360 versions of a handful of titles to get their Xbox One counterparts for as little as $9.99 per upgrade. Amazon will accept Xbox 360 games purchased from its website or elsewhere for an $25 bonus credit toward the same title on Xbox One on top of the 360 game's trade-in value. To take advantage of the deal, go to this page to select the Xbox 360 game being traded, then send the game to Amazon. Once it is received and the trade-in is accepted, players will be able to get the Xbox One version and the credit will automatically be applied to the purchase.

There is no PlayStation 4 upgrade offer at Amazon.

Games included: Assassin's Creed 4: Black Flag, Battlefield 4, Call of Duty: Ghosts, FIFA 14, Madden NFL 25, NBA 2K14, Need for Speed Rivals

Deal lasts until: Dec. 31.

Amazon UK

The same deal as Amazon in North America, only this one applies to both Xbox One and PlayStation 4 titles. Players must follow the same steps as above on this page and can get up to £15 in credit on top of their trade-in value.

Games included: Assassin's Creed 4: Black Flag, Battlefield 4, Call of Duty: Ghosts, FIFA 14, Madden NFL 25, NBA 2K14, Need for Speed Rivals

Deal lasts until: Dec. 31.

Best Buy

Best Buy offered a trade-in upgrade program for Xbox 360 games earlier this fall. Players who purchased Assassin's Creed 4 or Battlefield 4 by Nov. 24, FIFA 14 by Oct. 26 or Call of Duty: Ghosts by Dec. 5 are eligible for this offer. Players who purchased these games online or in store by the required dates should have received a $10 coupon via e-mail towards an Xbox One upgrade. The Xbox 360 version can then be traded in-store for a Best Buy gift card with a minimum value of $40. Buyers could then use the coupon and trade-in voucher and pay an additional $9.99 for Xbox One version.

There is no PS4 upgrade offer at Best Buy.

Games included: Assassin's Creed 4, Battlefield 4, Call of Duty: Ghosts, FIFA 14

Deal lasts until: Dec. 31.

GameStop (US)

PowerUp Rewards members must have purchased new versions of eligible Xbox 360 games within the first 30 days after the title's release date. Buyers receive $50 guaranteed trade-in credit and will only need to pay $9.99 or less to get the Xbox One version. There is no PS4 equivalent of the deal.

Games included: Assassin's Creed 4, Battlefield 4, Call of Duty: Ghosts, FIFA 14 Madden NFL 25

Deal lasts until: Dec. 31

Microsoft Store

For Xbox One games, Xbox 360 versions and purchase receipts can be brought to any Microsoft Store for an upgrade. Buyers must trade in the Xbox 360 and pay $9.99 to get the game's Xbox One version.

Games included: Assassin's Creed 4: Black Flag, Battlefield 4, Call of Duty: Ghosts, FIFA 14, Madden NFL 25, NBA 2K14, Need for Speed Rivals

Deal lasts until: Dec. 31.

PlayStation Store

Some PS3 games will come with a code to download the PS4 version off the PlayStation Store at a discounted price. In order to play the PS4 version, users will have to insert the PS3 disc into the PS4 console.

Digital purchases of PS3 games will not require redemption codes; instead, PS4 games will already be displayed in the Store at a discounted price for those who own the PS4 version. Ubisoft's Watch Dogs was initially included in this offer, but was swapped out for Injustice: Gods Among Us after the game was delayed.

Games included: Assassin's Creed 4, Battlefield 4, Call of Duty: Ghosts, Injustice: Gods Among Us

Deal lasts until: Jan. 31st, 2014 for Injustice; March 28 for Battlefield 4; March 31 for Assassin's Creed 4 and Call of Duty: Ghosts

Game-specific deals:

All marked PS3 copies of Battlefield 4 include codes that will allow players to download the PS4 version for only a $9.99 upgrade. Codes must be redeemed before March 28, 2014.

Future Shop is offering trade-in deals for FIFA 14 on both PlayStation and Xbox consoles. Trading in either the PlayStation 3 or Xbox 360 version will net gamers $60 in trade-in credit towards the next-gen version.