We know that T-Mobile will probably launch the HTC One X+ sometime this fall, but now we have even more details about this mysterious device. According to those ever-elusive “anonymous sources within the company,” the international version of the One X+ is code-named the HTC Endeavour C2 and will have a 1.7GHz quad-core Tegra 3 processor, along with Android 4.1 (Jelly Bean).

The device will also come with a new feature called ClearVoice, which is said to drastically improve overall call quality. (It will be interesting to see how this compares to HD calling on Sprint’s HTC EVO 4G LTE.) Additionally, HTC is working on an updated version of HTC Watch that will make it a bit more competitive, and HTC will even include a pair of UrBeats earphones. The latter is interesting, given that HTC previously indicated that it would no longer bundle Beats headsets with its devices.

The One X+ is expected to be released in the UK on or before October 1, so we should expect an official announcement sometime in the near future. I’d imagine that T-Mobile’s version would be released around the same time, but there’s no indication on exactly when we’ll see this phone stateside quite yet.

[CNET]