The HTC One A9 was originally unveiled to work with AT&T, T-Mobile, Sprint, and Verizon later on. We were even told that in December it would be able to be bought from them. Unfortunately, Verizon will not be allowing the One A9 to be used on its network.
At first, HTC said they would send out a software update to allow the One A9 to work with Verizon, but have now said it will never happen. The One A9 is a non-CDMA phone and Verizon is a CDMA network. It didn’t really make sense for the One A9 to be able to work, but HTC assured us that it eventually would. However, after testing and testing, HTC has said they were unable to support Verizon’s network.
HTC is committed to providing the best experience for all of our device owners. Following extensive testing, we are unable to support the Verizon network with the Unlocked HTC One A9. For individuals on the Verizon network that ordered the Unlocked HTC One A9 on HTC.com, we will refund his/her order and provide a 20% discount on any current HTC phone or future phones launching through Dec. 31, 2016. Individuals may contact HTC Care at 1-888-216-4736. We regret any inconvenience.
There is some good out of this, if you bought a One A9 and planned on using it on Verizon, you are entitled to a refund. HTC will not only be offering refunds, but also a 20% off discount on any current or future HTC phones until December 2016. At least you can use that discount towards a HTC 10 now.
Source: Droid Life