One of the most ambitious and challenging parts of Rock Band 4 for Harmonix was the promise of retaining all of the legacy DLC from previous games, both with the individual tracks that you could buy as DLC and with the exports that were possible from game discs and track packs.
In the EU, that side of things fell apart on PlayStation 4, but Harmonix have kept plugging away alongside Sony and now have a timetable for when these will be resolved for players.
- Rock Band 2 – January 2017
- AC/DC Live: Rock Band Track Pack – February 2017
- Lego Rock Band – March 2017
- Green Day: Rock Band – April 2017
- Rock Band Blitz – April 2017
- Rock Band 2 – 20 Free Songs – May 2017
- Rock Band™ Track Pack Vol. 2 – May 2017
It’s dragged out for over a year now, but they are finally getting there. More recently, Harmonix added to Rock Band 4 with the major Rivals expansion pack – reviewed here – including a new single player mode and the first multiplayer modes to be added to the game.
Source: EU Blog