https://www.pcgamer.com/sigil-john-romeros-spiritual-successor-to-ultimate-doom-is-delayed-again/

Sigil, the John Romero-authored "unofficial spiritual successor" to Ultimate Doom that was announced late last year, has been pushed back yet again. It was originally supposed to be out in February 2019, but was delayed into April because of problems with the planned physical release. Now April is here and it has slipped yet again, for the same reason, to the first week of May. 

The good news for fans is that the Sigil megawad is finished, and will still be free for everyone once it's out. But because Romero wants to ensure that people paying for the boxed editions have a fair first crack at it, the free release won't go out until a week after the paid release.