If you look at the Nokia windows 8.1 availability site you'll notice all CDMA Carriers are listed as still Under Test.
Microsoft shows Under Test to mean anything (carrier testing, MS testing, FCC testing, etc.).
The fact that ALL CDMA Carriers are Under Test tells me that other than developer edition for beta feedback, Microsoft has not yet released the final 8.1 update (nor its Cyan update to 8.1) to any of these carriers.
IMHO there may also be a gag agreement in reseller contracts preventing carriers from publicizing that they are still waiting on Microsoft to release the final version for these carriers to finally test, which would explain why NONE of the CDMA Carriers have answered any inquiries into 8.1 availability.
So as much as I like to hold carriers accountable and even file complaints with the FCC when appropriate, reality is this might all be on Microsoft and the carriers may be as helpless as we are.