Sony looks set to upgrade its flagship true wireless range soon, and is yet again applying a major redesigning to its WF-1000X series buds. 

For the WF-1000XM4 it appears Sony is changing the shape completely, opting for a much rounder casing to replace the flat, elongated pill-shape design of the current gen model.

The leaked image comes from MyDrivers and shows a round earbud with copper-coloured round protrusion next to it, directly beneath the eartip. 

That eartip itself appears to be made from foam, so it could be that the next generation Wireless Freedom buds are equipped with Comply tips (or similar foam-based tips) as standard. 

If so, that would likely improve the effectiveness of the noise cancelling passively, and improve the fit for each user over using the standard silicone tips. 

Unlike the over-ear series, the buds have seen a shift in design with each generation. The first gen model had a futuristic metallic sheen to the outside with a prominent LED light flashing in a transparent window at the end. 

The follow up series took a much more minimal approach, with a matte finished pill-shape. 

The one thing they've always done well is noise cancelling, whether passively or actively using the advanced ANC engine. And that's something that will likely continue and be improved in the next model too. 

We don't know much more about Sony's next series of TWS earphones, but we suspect with the image leaking from what looks like either an official document or packaging, that the launch isn't far away.