There was a lot of confusion recently when the HTC One might receive Android 4.4 KitKat and as a matter of fact, there's not the one HTC One. Beside having countless operator and open market versions, there's also the HTC One Google Play Edition as well as the HTC One Developer Edition. While the Google Play Edition and Developer Edition are somewhat confirmed to receive the upgrade within 2013, the biggest question left was when the regular HTC One will receive it? Now, HTC UK was so kind to go into details and unveiled that it expects availability for end of January 2014. As expected, the firmware has to go a longer process since HTC has to work here with its local carriers.
While the statement above came from HTC UK, I would expect that it is valid for all over Europe. Based on the recent updates and upgrades, I would even expect that Scandinavia and open market HTC Ones will receive the tasty KitKat upgrade first; maybe even a little bit earlier; followed by rest of Europe and its countless carriers.
Cheers ~ Arne