A few days ago announced the Sony Xperia Z5, Xperia Z5 Compact and Xperia Z5. Shortly after the announcement started rumors about the release of Xperia Z5 Ultra, which will probably take place in March 2016.
In the matter of features expected to come with the Snapdragon 820 with huge screen of 6.44 inches, resolution 4K. According to the rumors, he has 4GB RAM and 23MP camera, like the brothers of the Xperia series Z5. H battery will probably be in 4000mAh.
Of course none of this is not official yet, so it is advisable to keep a pool on the Xperia Z5 Ultra.