DOOM Retro v2.6.6 is now available. It may be downloaded here, and its release notes are as follows:

• Optimizations have been made to further improve the overall performance and stability of DOOM Retro.
• A bug has been fixed whereby the wall textures visible beyond a moving sector would shift slightly.
• Improvements have been made to how blood splats are spawned.
• Entering text in the console has now been improved for non-US keyboard layouts.
• Minor changes have been made to text that is output to the console.
• Early versions of DOOM Shareware will now run without quitting with an error.
• When the player’s health or ammo is low, now only the values themselves will flash in the default widescreen HUD.
• Multiple keycards and skull keys are now positioned better in the default widescreen HUD.
• A bug has been fixed whereby keycards and skull keys weren’t appearing at all in the alternate widescreen HUD.
• Keycards and skull keys in both the default and alternate widescreen HUDs now appear in the order they were picked up by the player.
• Minor improvements have been made to the alternate widescreen HUD.
• A bug has been fixed whereby a monster’s position would be interpolated when teleporting if the vid_capfps CVAR was a value other than 35.
• Giving the player and monsters infinite height can now be toggled on or off using the new infiniteheight CVAR. This CVAR is off by default and on when vanilla mode is enabled.