Here is the full message regarding the delay, via Grinding Gear Games:
When we announced Path of Exile for PlayStation 4 earlier this month, we indicated we were aiming for a December release. Unfortunately, we have had to revise this to early February. We are extremely sorry for the inconvenience this causes, because we know there are many players looking forward to this release.
We underestimated the amount of work it would take to finish the certification process during the busy Christmas period. While we hope to have everything ready in January, we feel a lot more comfortable promising early February as a target release window. This will also give us time to work on game performance/frame rate, which we feel could be improved before release.
Again, we’re very sorry about this. We understand that many PlayStation users were keen to play Betrayal over Christmas and have been eagerly awaiting release date news. We promise that Path of Exile will be awesome on PlayStation 4 when it is released early next year.
Path of Exile is currently available for Xbox One and PC.