It was originally expected that Sony would announce a new flagship phone at CES 2014 because that’s what they did back in 2013 with the Sony Xperia Z. Unfortunately that was not the case so the next best bet is MWC 2014. Rumors have also suggested that the phone could see a release in April, but presumably we will learn more once Sony has made their announcement.
In the case of the Xperia Z2, Sony could be keeping its quad-core chipset with the Qualcomm Snapdragon 800 MSM-8974-AB processor which could be clocked at 2.3GHz. The processor will also be accompanied by 3GB of RAM and an Adreno 330 GPU, making it a force to be reckoned with.
Battery life in the Xperia Z2 is also said to be getting a boost and will see it increase from 3,000mAh to a whopping 3,700mAh.