HTC One M8 receives latest OS and firmware from Verizon
Verizon rolls out an update to HTC One M8
The U.S carrier has started rolling out a new version of Windows Phone 8.1.1 (build 14203) and new firmware (build 21705) to the HTC One M8 smartphones which are not part of the Preview program.
If the Program for Developers is enabled the new firmware update cannot be seen, so you should temporarily disable the program, install the firmware and then re-enable the program. Keep in mind that the OS Preview build is newer (14219) so you will update only the firmware.
For regular smartphones, not part of the preview program, both updates (OS and firmware) are applied.
The new firmware build contains support for Softcard payments, fixed an issue when turning the phone on, improved stability and fixed sudden reboots.
Source: Verizon via Windows Central