If you owned any of the previous Rock Band games, it might be time to pull those plastic instruments out of the closet and dust them off because Rock Band 4 was just announced. Yes, the famous franchise from Harmonix is coming back and this time it's coming only to the PlayStation 4 and Xbox One.

Will your old instruments work from the Xbox 360 and PlayStation 3? Maybe. Will all of those DLC songs and imported tracks work? Sure!* *Assuming you aren't trying to go from 360 -> PS4 or PS3 -> XB1

Yeah, there's the catch. You knew there had to be one.

Here's the current deal as it stands from Harmonix. Harmonix is working closely with Mad Catz, Sony, and Microsoft to try to reach a "solution" for letting you use your old hardware on the new consoles. They say that it's something they would "love to happen" but there is nothing set in stone at all.

The good news about the music is that the content you purchased from the store or exported from a disc from the previous generation will transfer over just fine to the current generation of games so long as you stick to the same platform brand. That means importing will work just fine if you go from Xbox 360 to Xbox One but not Xbox 360 to the PlayStation 4.
Will my old DLC work if I bought a different next gen console, i.e. Xbox 360 -> PS4?
Cross platform DLC compatibility is not entirely within our control, as DLC ownership is managed by the 1st parties.

They also note that they will not include Pro Guitar or Pro Keyboard support in Rock Band 4. They note that they will include the Pro mode for the Drums, however. They also note that they are not working on versions of the game for other platforms at this time. Their full FAQ can be found at the Harmonix forums.

It should also be mentioned that Harmonix is offering a free piece of DLC right now for the PS3 and 360 versions of Rock Band 3 and Rock Band Blitz. It's "I Still Believe" by Frank Turner.