According to the new screenshot, the D6603 runs Android 4.4.2 KitKat. A previously leaked screenshot of a benchmark test suggested that the smartphone had features similar to what the Xperia Z2 is offering: a 1080p display, 20.7MP rear camera, a quad-core Qualcomm Snapdragon 801 (8974-AB) processor, and 16GB of internal memory. There was a difference in the RAM department, though: 2GB instead of 3GB.
There's no word on what the D6603 looks like, so it's impossible to tell if the handset's design is similar to that of the Z2.
Earlier this month, we heard that a Sony Xperia Z2 Compact might be in the making. Could this be related to the D6603? We can’t know for now, but we’re hoping to hear more on this soon.
Source: Digi-wo (translated) via XperiaBlog