Sony has detailed the official upgrade path allowing PlayStation fans to upgrade their PS3 copies of Assassin's Creed 4: Black Flag, Call of Duty: Ghosts, Watch Dogs, NBA 2K14 and Battlefield 4 to the PS4 version.
To take advantage of the offer you'll need to buy the PS3 game on either Blu-ray or digital, and for a limited time will receive entitlement to download a PS4 digital copy of the same game from the PS Store for the discounted price of £9.99 (£11.99 for NBA 2K14).
The PS3 Blu-ray versions will include a code in the box which can be redeemed on PlayStation Store. The original PS3 game disc will be required so make sure you hang onto it. Codes can be redeemed without a PS4 so you can register the code as soon as you buy the PS3 version.
If you buy a digital version of a supported PS3 game the PS4 version will show up on the PlayStation Store at the discounted price - no code will be needed.
The offer is only valid for a limited time, however, so make sure you don't miss out. Codes must be redeemed and purchases made before January 31, 2014 for Assassin's Creed 4 and Watch_Dogs; March 28 for Battlefield 4; and March 31 for Call of Duty: Ghosts and NBA 2K14.
PS4 launches in the UK on November 29 priced £349.
There are a few big games missing from the list, notably FIFA 14 and NFS Rivals, but these are upgradable through selected retailers.
Source: EU PS Blog