For the past two years, Sony Mobile could be counted on to introduce new Xperia smartphone lines at CES — the S and Z, specifically. Not so this year, as the companys instead offering twists on previously announced hardware, which, for the US market, results in the Xperia Z1S for T-Mobile. If you followed our IFA coverage from last summer, youll be familiar with what Sony and exclusive US partner T-Mobile have to offer.