This year's Mobile World Congress in Barcelona, Spain is fast approaching, which means that the soon-to-be released flagship smartphones from the top mobile manufacturing brands may finally see the light of day. 

Two of the highly anticipated smartphone launches that will coincide with the MWC 2015 are the Sony Xperia Z4's as well as the LG G4's. These are two high-end smartphone products that are believed to be the improved versions of their predecessors. 

A lot of rumored specs have been released about the two upcoming products, but none of them have been confirmed or denied by their respective manufacturers. 

Here is an updated comparison between the two upcoming smartphones:

Sony Xperia Z4

The alleged flagship phone from the Japanese consumer and mobile phone brand is rumored to come out with a glass back panel and metal side frame to enclose its internal parts. It also reportedly features the same nylon padding located along the edges that was earlier seen on the company's Xperia Z3 device, and has a whopping 5.2-inch IPS LCD capacitive touchscreen. 

It is also equipped with a 64-bit Qualcomm Snapdragon 810 chipset combined with a 2.8 GHz octa-core processor and a bigger 4 GB RAM. 

The Sony Xperia Z4 is rumored to be unveiled during the Mobile World Congress on March 2.

LG G4 

Meanwhile, the South Korean mobile and electronics company will reportedly reveal a new and improved flagship phone that has a bigger 5.3- to 5.7-inch screen with a 3840 x 2160 pixel resolution. Speculations also claim that the new G4 has a flexible screen that works well with a new G Pen Stylus. 

It is also equipped with a quad-core 1.5 GHz Cortex-A53 and quad-core 2 GHz Cortex-A57. 

Both smartphones are expected to be available in 32 GB and 64 GB varieties, and they can be both expanded up to 128 GB using the microSD slot. They will also allegedly run using the latest Android 5.0 Lollipop operating system when they are released in the market this year.