The news, first spotted by Rockstar Intel on an image (see it below) for a PlayStation 4 Pro Red Dead Redemption II bundle revealed by American retail giant, Target
File sizes vary across platforms but it's safe to assume that the Xbox One version will have a similar size for the install. That means you have just under one month to clear some of that backlog and make space for the biggest game of the year.
The image in question also revealed that Red Dead Online will support up to 32 players, putting it close to the player count for GTA Online. Eagle-eyed fans will also notice that "select online content" will be exclusive to PlayStation 4 for 30 days.