HTC announced on Thursday that the majority of HTC One users in the US are one step closer to seeing Android 4.4 KitKat on their handset. HTC has rolled out its KitKat update to Verizon, Sprint, AT&T and T-Mobile for final carrier testing, and certification is expected to come next week.
This means the update has reached the third of fourth stages before being pushed out over-the-air to users' handsets.
The update is now in carriers' hands to install their own custom software and run tests, and then the software is ready. At this stage, users are simply at the mercy of carriers, not HTC, to release the update.
HTC had previously promised January, but the days are quickly running out. If you're wondering why this applies to the US only, that's because HTC US details these upgrade steps. For the UK, there's no such information. We can only assume that HTC is in a similar position in territories outside the US, so an upgrade can't be far off.