According to the documentation, you can set the mediaFileURL of a custom message to an audio file - which will play and display with a graphical waveform representation.
As far as I can tell (based on other posts, testing, looking at code), this is not the case at all.
What's really irritating is that if you use a video file, it works, but the video is perpetually muted - there appears to be no way for the end user or the developer to enable sound.
Yes the issue does seem to be that the audio is muted. I'm looking into if we need to do additional handling on when a message is selected. As of now it seems that insertAttachment: is one way to get around it but you dont get the nice card view that you get with MSMessageTemplateLayout with the Title and Subtitle that my client wants to use. Please let me know if you've found a way to make this work, it looks to me like the Messages App Chatterbird was able to make it work.
