The unlocked HTC One is in the midst of getting a small (17.55MB) OTA update this evening, bringing the version number to 1.29.xxxx.17. The device has hit our developer edition HTC One, and is tagged only with the obscure but ever-present "System Enhancement" bullet point in the update prompt.
HTC hasn't posted any change log at this hour, but we know you Android junkies needed to know about any OTA, no matter the time. If you want to grab this one -- rooted users consider any consequences -- grab it through your system settings.
No word on when we'll see anything similar for carrier branded devices, we'll reach out tomorrow when our HTC folks get out of bed.