Sony is expected to unveil a new flagship phone during Mobile World Congress in Barcelona next month; the much-rumoured Sony Xperia XZ Pro.

We've heard a few speculative, promising details about it over the last week or two, including its alleged 4K HDR OLED display, but the latest leak will likely be less well received.

According to a filing with the US communications regulator, the FCC, the next Sony flagship smartphone will come without a headphone jack.

A diagram included in the filing is imprecise in showing the actual connections at the bottom of the handset, but it does hint at a dongle.

Sony/FCCSony Xperia Xz Pro To Ditch The Headphone Jack image 2

It shows an external adapter with, presumably, USB-C power and 3.5mm headphone jack ports, and then a USB-C connector that goes into the bottom centre of the phone.

Bad news for Sony mobile fans who usually gloat at their iPhone and other non-jack smartphone sporting chums.

The same documents also reveal the dimensions of the phone (152.79 x 72.42mm) and confirm that the display will be 5.7-inches, as often rumoured. However, there is little else to glean from the filing.

We'll no doubt see the phone in its full splendour during MWC 2018, which starts at the end of February.