TrustedReviews has posted a report on a supposed leaked document that includes a bunch of details on Red Dead Redemption 2 including the online mode and its open world. TrustedReviews originally received the documents in August 2017, but have held back on publishing the story as they've been waiting on corroborating evidence. Evidence they feel they've got with recently released screenshots.
According to the documents received by TrustedReviews, the online mode will be more ambitious than in any previous Rockstar title. Three modes were also revealed as part of the online component: Battle Royale, Revive and Survive and Money Grab. The former is clearly a mode that takes a page out of the PUBG/Fortnite book, but it's perhaps doubtful that it will actually play exactly like that in Red Dead Redemption 2.
As far as the solo campaign goes, there's seems to be a certain degree of branching narratives and potential for player actions to influence the story. We're talking about choices that could potentially alter the outcome of a mission. Furthermore, you'll be able to trigger specific dialog options if you injure someone in a certain way or send them flying off a horse.
Open world activities are said to include "gold-mining, fishing, herding and an assortment of weapon challenges". Particularly fishing seems to be a rather deep side activity, and there also appears to be plenty of crafting.
It's not a great surprise that first-person mode will make its way over to Red Dead Redemption 2, both in singleplayer and multiplayer. Dead Eye is also set to make a return.
As usual with these kinds of leaks, they need to be taken with a grain of salt, and even if authentic one needs to consider that quite a few things can change from August 2017 (at the latest) until the release of the game in October this year.