New reports are claiming that the Sony Xperia Z4 has been certified in Indonesia, which takes the future smartphone a step closer to its official unveiling.

According to Xperia Blog, Indonesian Postal Regulatory has given its approval to three new Xperia handsets bearing model numbers E2353, E5333 and E6533, which is the said to be the Xperia Z4. The site claims that the device followed Sony's naming scheme on the Xperia Z lineup. Z2 came with a model number that starts with D65xx and the Xperia Z3 with D66xx. The other two certified are believed to be a follow-up to Xperia M2 and a mid-range handset. 

In addition, the alleged Xperia Z4 is said to have been approved by the Ministry of Internal Affairs and Communications in Japan as well as the Federal Communications Commission. 

The Sony Xperia Z4 is rumored to come in two sizes. Reports are conflicting about these though. Many expect one to go for a 5.1-inch Quad HD Display while others say that it will be relatively bigger at 5.2 inches. This however, is speculated to render 423 pixels per inch and a 1080p resolution. The bigger version of the Z4 is touted to get a 5.4- to 5.5-inch screen, which should be insanely sharp with a 565 ppi pixel density and a 1440p resolution. 

In terms of design, the forthcoming Sony offering is coming with a glass structure and a metal edge. The first-class look will then be paired with a waterproof design for the device to look good while remaining heavy-duty. According to Phone Arena, the phone's bezels will be reduced, which will make it lighter than its predecessor.

As for the Z4's innards, Sony is expected to make use of a Qualcomm Snapdragon 810 processor to power it up. There will be 3 GB RAM for the smaller Z4 variant while the larger kin will get 1 GB more. Storage capacity-wise, the Sony Xperia Z4 should offer 32 GB, 64 GB and 128 GB, if not a micro SD card slot.

While the Z3 was already a shocker in the camera department, Sony will ramp its successor up by packing it with a 21-megapixel Exmor RS IMX230 camera. For the front-camera, the tech firm may opt for 5 megapixels.

Many anticipated the Sony Xperia Z4 at the Consumer Electronics Show 2015. However, Sony did not set up its stage there. In turn, fans will be looking for the handset at the Mobile World Congress to happen in March.