it seems to be the case. According to [0] Twitter just hired the devs without the legal entity behind Mitro, and seems like with no intention of supporting the project going forward.

[0]https://groups.google.com/d/msg/mitro-dev/cgFhvuPyUiE/o-sFkE... (Legally speaking: Mitro is run by Lectorius Inc, which has no legal relationship to Twitter Inc. It is a wholly owned independent company.)