Hello Sycraft, I have the same issue as you and I was kindedly directed by scook.
Currently I have "Lexington" and the current Command Center, I've paid (1/5/2016) in-full for the year, and the Sonar site stated that Manchester was released and it doesn't load into CC? There is no information on Cakewalk that addresses this issue, so I was hoping that the Sonar Forum could help, "the members are great"
The funny thing is, I saw for a while that Manchester was available and just waiting for it to load into CC?

Possibly contact support.