The HTC One X is one of the best handsets that money can buy around the world at the moment and it is on AT&T in the US. However HTC may already be looking towards the future with the Endeavour C2, otherwise known as the phone to take over the One X and it is said to come with a 1.7GHz quad core reports Androinica.
HTC One X successor dubbed Endeavour C2 (rumor)
The handset is also said to come with improved battery performance, it should be available in another colour choice and it comes with Beats earbuds packaged with it. In regards to software there are rumors that the handset will have HTC Watch 2 and it should be launched with Android 4.1 Jelly Bean pre-installed. It has been suggested that the launch for the handset will be around 1st October.
Just a few weeks ago there were rumors of the HTC Era 42 floating around for launch on T-Mobile with a 1.7GHz quad core processor. With this in mind it could be the successor to the One X and may be known as the One X+ i.e. the same device as the Era 42 but for T-Mobile instead of AT&T.