If you plan on purchasing Battlefield 4 for you current generation Playstation 3 console and then upgrading it to the PS4 version once that console is released then you’ll need to watch out for specially marked retail copies of the PS3 version.
They’ll include a voucher code (good for one-time use) that will allow you to upgrade your game to the Playstation 4 digital version for a small fee. Upgrading to the digital version makes sense as it can all be done online and you won’t need to swap/trade discs.
The offer is likely to be popular with hardcore Battlefield 4 players who, if they pick up the PS3 version on October 29, will have just over two weeks extra time to hone their skills before the Playstation 4 is released and people can start playing the game on that console.
Just to confuse things, the PS4 version of Battlefield 4 will actually be available in stores from November 12 (although you obviously won’t be able to purchase a console to play it in until November 15 in the US and November 29 in the UK). The Xbox One version of BF4 will arrive on November 19.
PS: The open beta for Battlefield 4 on the PC, PS3 and Xbox 360 will start on October 1. If you are interested in participating, head over here.