Sony might have just
XDA Forums member iRimas has shared several images of a Sony smartphone with model number D6503, which is being called an upgraded version of Xperia Z1 smartphone. Not many details are available about the smartphone at this point as the XDA member iRimas is not able to get the prototype working.
If it is indeed Xperia Z1 refresh, it could be the rumoured Sony Sirius smartphone, which according to @evleaks will feature a 5.2-inch display and Qualcomm’s quad-core MSM8974AB SoC. Sirius is expected to be announced at Mobile World Congress 2014, which is scheduled for late-February.