HTC recently indicated via its official Twitter account that it plans to update the Verizon version of the One to Android 4.3 by the end of the year and then to Android 4.4 by the end of January.
All other versions of the One will receive Android 4.4 by the end of January, too. HTC also indicated that it will update the Droid DNA to Android 4.4 and Sense 5.5 by the end of the first quarter, pending carrier certification.