This is according to a recent sighting at the FCC (via Xperia Blog) in which based on the schematics that were filed, there is a hint that the 3.5mm headphone jack might not be included with the phone. Of course this is just one handset and it could be that any other handset Sony might announce at the event will retain the port, but based on the schematics it hints that at least one handset might not have it.
The removal of the 3.5mm headphone jack is one that we’re starting to see more OEMs start to adopt. This is because the port takes up space and really serves no other purpose other than to pipe audio through it (for the most part). This is versus the current solution which is to use Lightning/USB-C in which one port can serve multiple uses, plus there are also claims that sending audio through Lightning/USB-C will be of better quality.
Sony has also been beefing up their wireless headphone offerings, such as the Sony MH-1000MX2 noise cancelling headphones, which many claim is giving Bose’s own noise cancelling headphones a run for its money.