Sorry for the cheesy subject title.
In King v. United States, --- F.3d ---, No. 17-10006 (9th Cir. 2018), the Court dismissed as moot the defendant's appeal from the district court's revocation of supervised release.
Adopting the reasoning of Spencer v. Kemna, 523 U.S. 1, 8–16 (1998), the Court held that an unconditional release from custody
moots a defendant's challenge to his allegedly erroneous
revocation. Thus, "[b]ecause King has been released from custody with no
supervision conditions, Spencer’s mootness standard applies." (Emphasis added).
The key thing to remember is that, if there were additional supervised release, the appeal would not be moot.
Also, the Court rejected the defendant's argument that the appeal was not moot because the revocation charge involved a
finding that he committed statutory rape, which theoretically could
require him to register as a sex offender in the future. The Court found this remote possibility was "too remote to constitute the 'concrete and continuing injury' required to avoid mootness."
