Board Thread:General Discussion/@comment-2212553-20171210185236/@comment-5486221-20171211012835

They kinda hinted at it before the video. Upgrade is the only one of the original 10 aliens who doesn't have an Omni-Enhanced form, plus he didn't appear in Dr. Animo's mutation sequence in Animorphosis. I hope they explain why he got sacrificed in-series, though.