HTC is readying the next flagship device HTC M8 for a launch later in March. It has not been very fast in rolling updates as well. It has started rolling out Android 4.4 KitKat update coupled with Sense 5.5 for HTC One for four carriers in US but there was no word on global roll out till now. But barring the HTC One, there are two other flagships as well, the HTC One Max and One Mini which had not received any word on the update till now.
What hints towards the same that HTC has stated the fact that it has ideas like this "under consideration" and it keeps on looking for ways to streamline the updates and make them available speedily. The Android updates are usually delayed because after a manufacturer releases them, they are tested individually by the carriers which take up a lot of time. Back in India, the carriers are not responsible for the same and we get updates without any sort of carrier testing.