The remastered Quake is available now on Nintendo Switch, PlayStation 4, Windows PC, and Xbox One, and is playable through backward compatibility on PlayStation 5 and Xbox Series X. On PC, Steam and Bethesda Launcher users who already own Quake will automatically receive the new version with a free download.
In terms of visuals, players can expect improved lighting and models, dynamic shadows, motion blur, and anti-aliasing. The game’s score, produced by Nine Inch Nails’ Trent Reznor, is also included. Expansion packs Scourge of Armagon, Dissolution of Eternity, and Dimension of the Past (the new, MachineGames-created add-on), are now included as part of the standard Quake package. More details are available at Bethesda’s announcement.
I don't know anything about Quake source ports or whether they support any of this new content, but I suspect that if they don't now they will eventually.