Now, there is a chance that Sprint customers sporting HTC's flagship Android model can manually pull the update out of their phone. Technically, this is called a customer initiated request. You go to Settings > Software Update > Check New. If the results are negative, be a little more patient. Software update 4.06.651.4 will start its network rollout on February 14th.
Last week, we passed along a leaked HTC update roadmap and it showed that the carrier branded HTC One would receive the Android 4.4.2 + Sense 5.5 update anytime between late January to mid February. Looking at what is happening from that standpoint, it looks like HTC will be delivering the goods right on time.
A customer initiated request could pull Android 4.4 out of your Sprint branded HTC One
source: Sprint via AndroidCentral