As of July 2018, any Verizon Wireless phone that uses CDMA for voice and not compatible with VoLTE and HD Voice can't be activated on the Verizon Wireless network. Any phone already activated prior to July 2018 can remain active on the network until Verizon Wireless starts notifying users to switch to a newer device.
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We are sorry to see that you are having difficulties activating a HTC One M8. We are here to help and see what is going on with the activation. We recently updated our services and only 4GLTE phones with Advanced Calling will be compatible in our network. Unfortunately, the HTC One M8 is not compatible with the Advanced Calling service. You are more than happy to take a look at our latest devices at www.vzw.com.
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