Recent reports on Sony's upcoming flagship, the Xperia Z4, have centered on the device's alleged form factor.

Citing information from FutureSupplier, Phone Arena took note of the smartphone's purported chassis. When compared beside its predecessor (Xperia Z3), the new handset appears to be 0.04 in (1 mm) thinner, with an estimated depth of 0.25 in (6.3 mm).

Users would know that the iPhone 6 has a depth of 6.9 mm, while the larger iPhone 6 Plus comes at 7 mm.

Unwrapped in this year's Mobile World Congress, the Samsung Galaxy S6 owns a thickness of 6.8 mm, while its brother Galaxy S6 Edge comes with 7 mm.

To compare, it's evident that the Xperia Z4 wins battle in terms of depth -- that is, if the report holds absolute truth.

Phone Arena went on to inform that the flagship may not possess one of the Xperia line's most-recognized strengths. The source wrote, "From what we're told and shown, it appears possible (but unlikely) that Sony has ditched waterproofing."

This seems to be a move similarly done by Samsung. For the newest Galaxy S6 / S6 Edge, the Korean tech giant has ditched waterproofing abilities present in the Galaxy S5. The earlier flagship holds an IP67 certification, allowing submerging at a depth of 1 m for a maximum duration of 30 minutes.

If Sony joins Samsung in such retraction, Apple could be laughing its way instead. Apparently, a recently-published patent has suggested the company's efforts in crafting a waterproof iPhone. The technology aims to protect integral components with a hydrophobic coating, done through plasma-assisted chemical vapor deposition (PACVD).

The alleged Xperia Z4 leaks also suggest that the device will own an open port, GSMArena reported. This looks to be a clear difference from the Xperia Z3, which had a flap to cover its microUSB port.

The outlet compares such open port to that of the Xperia M4 Aqua's.

Back in October, TechRadar is convinced that the Xperia Z4 could be the "world's most powerful smartphone." At the time of reporting, the device is pegged to have a 5.5-inch QHD display (1440 x 2560 pixel resolution), a 64-bit 2.8GHz octa-core Snapdragon 810 processor, 4 GB of RAM, Adreno 430 GPU, 32 GB of storage, 20.7 MP camera sensor, Bluetooth 4.1 and LTE Cat.6 connectivity support.

In a recent article, Trusted Reviews has noted of similar specs, adding that the Xperia Z4 "will be licking Google's Lollipop direct from the box."

The smartphone's arrival is more strongly believed at the present, following Sony's launch of the Xperia Z4 Tablet. The device comes with a 10.1-inch 2K display, weighing 389 grams for its Wi-Fi version. It runs Qualcomm's Snapdragon 810, clocked at 2 GHz.

The device, however, is both water- and dust-proof, having IP65 and IP68 certifications.

Expected to arrive in Q2, the Xperia Z4 is speculated to retail for $1,250.