John Romero has announced that Sigil, his upcoming "unofficial spiritual successor to The Ultimate Doom's fourth episode", has received a slight delay.
Sigil, which was announced on December 10th last year, in celebration of Doom's 25th anniversary, was originally anticipated to release in mid-February 2019, so around about now. It's a completely free episode (although several physical editions were available to purchase), and will include nine single-player and nine death match levels.
Notably, Sigil will be distributed as a megawad - the same special asset-bundling file format used by Doom back in 1993 - meaning that players will require a copy of the original game in order to play it. Incidentally, those Doom-less among you might like to know that The Ultimate Doom is currently discounted to 1.59 on GOG, if you're keen to prepare for Sigil's arrival.