UPDATE: We were able to fix the problem and have already made the update available in our beta program. So you can try out version 2.5.0 early now:
Samsung has released the update to Android 9 (Pie) for many Galaxy smartphones since the beginning of the year, but we recommend to stay with Android 8 (Oreo).
The update to Android 9 is available for the following devices:
- SAMSUNG Galaxy S9 (January 2019)
- SAMSUNG Galaxy S9+ (February 2019)
- SAMSUNG Galaxy S8 (March 2019)
- SAMSUNG Galaxy A7, A8, A9 2018 (April 2019)
Some users report that after 5-10 seconds of a VoIP call they are no longer understood by the person they are talking to. The audio channel doesn't seem to get lost, but they can only hear it when talking very loudly directly into the microphone (or blowing). Samsung probably tries to suppress ambient noise with the additional microphones in a different way or switches off the microphone too early if you don't speak (silence detection).
As we are dependent on a correction by Samsung according to the current state of knowledge, we recommend to avoid the update to Android 9 on all productive Samsung Galaxy devices for the time being, as with all major OS updates.
If you have already updated your Samsung Galaxy to Android 9 and can't undo it, you should try to use a headset (via cable or Bluetooth), as this way the control of the smartphone's microphones can no longer have a negative influence on the call transfer.
Please let us know by comment or email at firstname.lastname@example.org if you can confirm this behavior and if using a headset will work around your problem. Thank you very much.