Bungie issued an update earlier discussing what’s going to happen with the content for the Destiny 2 Content Vault.
If you recall, Bungie first introduced this Content Vault in June which would add new content but also reintroducing some older legacy content into the current game. To that end, November 10 marks the beginning of Year 4 of Destiny 2. This means that Io, Titan, Mars, Mercury, and Leviathan are going to enter this Content Vault. The goal is to make the way for the Cosmodrome and the debut of Europa.
Bungie took care to answer a popular question regarding the vault, mainly by reiterating a “rule of thumb” regarding content. This rule of thumb is effectively that whenever a destination enters the vault, all its PVE activities and all its associated rewards will enter the vault with it.
The rest of the post makes note of any Strikes, Gambit, Gambit Prime, Crucible, Raids, Dungeons, and weapons entering the vault with the start of Year 4 on November 10. You can take a look at the full list here.