How do I download / install updates to Rock Band 4?
Both consoles should automatically prompt or download the most recent update while connected to the internet. If you are correctly connected to the internet, you have the latest version of the game.
Your Xbox One should prompt you to download a title update once you choose to play Rock Band 4, should the latest update not be installed at the time. If you decline this prompt, you will be taken offline and continue to be prompted to update anytime you play the game. If you require further assistance, please contact Xbox Support.
Your PlayStation 4 should automatically begin downloading any title updates to Rock Band 4 once it is turned on or woken up from Rest Mode. The only time this would not happen is if you have manually turned automatic updates off. Please refer to this link for installing and updating Rock Band 4 on PlayStation 4 (located under "Application Update Files"). If you require further assistance, please contact PlayStation Support.