A report from Greek websiste Techmaniacs suggests the incoming flagship will pack the latest Qualcomm Snapdragon 810 chipset. This is highly likely, as the majority of 2015's new phones are expected to feature it too.
There were reports last year that claimed Qualcomm was experiencing a delay in shipping the processors due to overheating issues, but Qualcomm has rubbished these and says it's on track.
Elsewhere there's expected to be a Quad HD (2K) display and 16-megapixel camera. It's not clear what screen size we can expect, but the Greek site is reckons it'll land with a 5.3in display and 3GB of RAM.
If true, it'll be an interesting step for LG, given that the current G3's screen is 5.5 inches. A 2K 5.3in screen will make the G4's display one of the sharpest around.
The website has also received leaked images of the camera's 16MP resolution, with it reaching 5312 x 2988 - some improvement over the 13MP snapper found in the G3. There's no mention of LG's laser autofocus or optical image stabilisation, but we'd be surprised if they didn't make a return.
LG hasn't commented on these rumours, nor has it released any official information. It's unclear when we can expect a full reveal of the phone, but with Mobile World Congress taking place in March, it's possible the G4 could take centre of LG's stage.
Given the importance of the G4 however, it's more likely that LG will hold its own event, possibly around the end of May, which was when the G3 was revealed last year.