http://wccftech.com/iphone-8-iphone-x-apple-tv-4k-listed-with-support-for-flac-lossless-audio-format/

You love your lossless music, don’t you? Then you’ll be pleased to learn that the iPhone 8, iPhone 8 Plus, iPhone X and the new Apple TV 4K support playback of FLAC audio files.

With the release of iOS 11 Beta, a lot of things started to surface which Apple just did not announce on stage. Support for playback of FLAC lossless audio files was one of them. But the thing is – you just can’t go ahead and copy FLAC files on your iPhone and start listening to them. This means support for the format in the native Music app was out of the question. If you are going to listen to FLAC, then you have to copy your audio files to iCloud Drive and then access those bits using the Files app.