According to numerous user reports, it seems that the update for the HTC One M9 has started to roll out. This has also been confirmed on Sprint’s website in which they also mention that the update might not necessarily be available for everyone right away. This is common as updates are rolled out in phases.
So if you do not see the update available for download on your phone just yet, fret not as neither HTC nor Sprint have forgotten about your device, but rather it will make its way to you over the course of the next few days. Of course Sprint’s release of the update is a little later than the unlocked version, but that’s usually the case with carrier releases as it needs to go through one extra stage of approval.
But hey, better late than never, right? In the meantime for those who can’t wait for the notification, you can attempt to try and manually fetch the update by going to your phone’s Settings, but if it isn’t there, you’ll just have to wait for it.