For better or for worse, wireless audio is slowly becoming the norm for mobile phones and tablets. This has caused a lot of discomfort, but there are also benefits. One is the ability to send audio signals to two separate Bluetooth devices simultaneously. Some Samsung phones can already do this, and according to a rumor of Japanese blog Mac Otakara (seen through Mac Rumors ), Apple could also bring the feature to future iPhones.  Being able to connect to more than one Bluetooth device can be useful in a variety of scenarios. You may want to connect your phone to your car's audio system to give GPS instructions while playing music through headphones, for example. Or, you and a friend may want to watch a movie on a long trip. Being able to connect to multiple sets of headphones will allow you both to enjoy the full audio experience. (To be fair, if you have a device with a 3.5mm jack, you can only use a headphone splitter for the same effect).
Samsung's dual wireless audio feature is available on several devices and requires Bluetooth 5.0 to function. As noted Mac Rumors if Apple implements dual audio in the same way, it could bring functionality to older iPhones that support Bluetooth 5.0 (including iPhone 8, iPhone X and iPhone XS) through software
But do not get too excited, since the source of this rumor is not surprising. Mac Otakara cites a source in the supply chain, but does not say which iPhone model the function might be receiving. We'll have to wait a little longer to see what happens next.