With the release of the Z4 tablet during this year's Mobile World Congress in Barcelona, Sony might be already looking into targeting 2015 as the year that would complete its flagship line up with the release of its Z4 smartphone counterpart.

Rumors have been circulating about the latest device to come out from Sony. According to tech observers, the new flagship smartphone from the company will be a twin to its predecessor, the Z3. Of course, Sony's previous works in the past have cemented its reputation of foregoing massive shake-ups to its products if the current forms are already successful, and instead the company focuses on upgrading the hardware specs of upcoming ones.

However, leaked images that are making its rounds online seem to indicate that Sony will be taking a new direction with its upcoming handset. In the photos, seen on a foreign site and reported by GSM Arena, the upcoming Z4 will still retain its form factor, but with subtle changes.

The photos are cases for the Z4, and the cutouts on the cases indicate that first, the microUSB port will be moved at the bottom of the phone. This indicates that Sony might do away with the magnetic charging connector and instead concentrate on charging via microUSB, or wireless charging if the company chooses to incorporate it on the upcoming smartphone.

Meanwhile, there are also reports that aside from releasing a smartphone predecessor to the Z3, Sony might enter again into the phablet market. A hybrid phone and tablet, devices under this category are measured to be at least 6 inches and above.

Sony is reportedly working on a 6-inch phablet dubbed the Z4 Ultra, which will be the successor to last year's Sony phablet the T2 Ultra. No details yet has been made available regarding the rumor, but the hardware specs should closely match that of the Z4 smartphone like what Sony has done in the past.