With Sigil II release looming in December, I am addressing the "disservice" to the famous Romero mod, which was previously only supported by Tartar in its "compatibility" version. True, the way Sigil plays does not change depending on which version is loaded. However, reading through Sigil II anticipation threads got me believe that at least one reason for this great mod's special appeal to Doom fans is due to it being "that fifth Doom 1 episode". So, what the new build of Tartar brings is support for defining custom episodes in Doom 1. Also a "shim" WAD for Sigil is provided that ensures correct level progression, gives levels appropriate names and music and shows art from the WAD in the finale.
While this is not achieved by reading information in UMAPINFO format that Sigil provides, the engine changes are not mod-specific and allow similar treatment for other notable WADS that add fifth episode to the game - like 2022 Doom Odyssey, "shim" for which is provided but requires playing it in Doom II with Doom 1 IWAD loaded for the textures and resources at the moment. 
Another set of "shims" included allows for less distraction with to out of place images or original Doom II text screens, when following the story of Hell to Pay, Perdition's Gate or Demonfear through Demonfear MIDI Pack features. All three use intermission screen assets to tell it, so only relevant part of the intermission will be displayed.
Note: For "shims" to be loaded by Tartar their file names must match exactly the names of the to be loaded PWAD files. "Shims" for Sigil and Perdition's Gate are provided as SIGIL.WAD and PERDGATE.WAD. In case your WAD filenames are different, e.g. SIGIL_v1_21.WAD, PG-RAW.WAD or PG-RAW-X.WAD, corresponding "shims" need to be renamed accordingly.
The new build also makes music playback with OPL devices (Adlib, SoundBlaster and such) more accurate. This is noticeable with Doom 1 and Doom II music, but also with PWAD-s like BTSX episode 2 that provide OPL instrument timbres of their own.
Concluding with the list of less noticeable changes the published build has. See you in a month for the next update!
- Bugfix for Doomguy face suddenly showing as healthy when changing screen side
- Bugfix for weird colors when switching between multiple loaded color palettes on the fly
- MIDI files in RIFF envelope (like some of the original Bobby Prince ones) can now be played
- Screenshotting possible in more places of the UI
- Small changes to automatic mode of music track randomizer
- Console output for startup reorganized and unneeded verboseness removed
- When Text startup mode option is on, all entries from when starting the game will be shown in console
- No longer offer Nightmare difficulty mode when very old Doom 1 IWAD-s are loaded
