Sony has had some success with their Xperia Z3, and the long awaited Z4 (and possibly the Z4 Ultra tablet) should be getting an official release date soon.  From what we know of the specs, we can list off many rumors of the Sony Xperia Z4.  According to Know Your Mobile, Sony Xperia Z4 has already appeared in certification documents at both the US FCC and Japan's equivalent body.   

One of the biggest controversies behind the Sony Xperia Z4 is what type of display that it could have.  The rumored size ranges from 5.2 to 5.5 inches.  Some have speculated that the display will have 1440 x 2560 Quad HD resolution, which is becoming the new standard of Android phones.  However, the Sony Xperia Z3 had a 1080p screen, which really made it easy on battery life.  The Z4 could take the 1080p road if it wanted to give its users a longer lasting battery. 

Android Authority's recent rumor roundup of the Sony Xperia Z4 has also revealed another speculation about its processing package.  Some say that the Sony Xperia Z4 will use the Snapdragon 805, the identical chip in the Galaxy Note 4.  Others are saying that the Sony Xperia Z4 will contain the Snapdragon 810, which is the same chip expected to be in the newest flagships of HTC, Samsung, and LG. 

Then there is the James Bond connection. It is rumored that there will be some serious product placement of the Sony Xperia Z4 in the next James Bond movie, Spectre.  There are even rumors going about saying that James Bond actor Daniel Craig and film director Sam Mendes could have some input in the design of the Xperia Z4. 

Then other rumors point to the camera to be 27 Megapixels with a G+ Sensor.  There are rumors that the Xperia Z4 could be smaller at 20.7 Megapixels.  We have also reported on a Walkman edition, as well as a Tablet version of the Z4.  We'll have to see about that. 

We'll also have to see about other rumored features include a Qi wireless charging feature.  For those who are not aware, wireless charging is when you can put your phone on a special type of surface and charge your phone without needing to connect a cable.  This is starting to become a standard feature, and I wouldn't be surprised if all phones have this in the next five years.  The Sony Xperia Z4 is also going to be water-proofed, but I'm not certain to what extent. 

Of course, the question on everyone's mind is when Sony is finally just going to announce that.  All signs seem to point to Mobile World Congress in early March.  Chances are, it will be at the same time when Samsung announces the Galaxy S6 and HTC will announce the One M9.  It was rumored last year that CES 2015 could be the time when this was announced, but that opportunity has passed. 

Xperia Z3 will get Android L OS Update in February

Meanwhile, Xperia Z3 is still going strong as Sony's current flagship phone has been confirmed to get the Android 5.0 Lollipop OS update in February along with the slightly older Z2.

A manual download is available for the Z2 and Z3 now on the XDA developers forum, but that software is experimental and doesn't include all features that are found in Lollipop. The question is, though, will the two phones update to 5.0 or straight to the latest 5.0.2.

The Z2 and Z3 are not the only existing Sony devices that will be receiving the Android Lollipop update, though. Sony has confirmed that the mobile operating system update will be coming in "early 2015" to the Xperia Z, Xperia ZL, Xperia ZR, Xperia Z1, Xperia Z1S, Xperia Z Ultra, Xperia Z1 Compact, Xperia Z3V, and the Xperia Z3 Compact.