Henriquejr spotted that DOOM and DOOM II got an update on Steam:
More information.DOOM + DOOM II Release Notes
DOOM + DOOM II are back in a combined release with new content and features!
Developed by id Software and originally released in 1993, DOOM pioneered and popularized the first-person shooter, setting a standard for all FPS games. The critically acclaimed sequel, DOOM II, followed in 1994.
Now the definitive, newly enhanced versions of DOOM + DOOM II are available in a single combined release on Xbox One, Xbox Series X|S, PlayStation 4, PlayStation 5 and Nintendo Switch, in addition to PC platforms and Game Pass (subscription required). This definitive enhanced version is our biggest effort yet with online cross-platform Deathmatch and Co-op for up to 16 players, community-published single-player mod support (with in-game mod browser), optimized renderer, accessibility options, optional modern IDKFA soundtrack by Andrew Hulshult (including brand-new DOOM II recordings) selectable alongside the original MIDI soundtracks, presented in up to 120hz in 4K on supported platforms (see FAQ below for details) and a brand-new episode "Legacy of Rust," with new weapons and demons made in collaboration by individuals from id Software, Nightdive Studios and MachineGames.
Note: Existing owners of DOOM (1993) and / or DOOM II on any of the above platforms receive a free upgrade to the new combined game, and can still access their previously owned versions. (See FAQ below for details.)