When connecting to a group voice chat/voice call/video call, it is not possible to hear anyone and other participants are unable to hear you. Voice/video messages work without any issues.
You will not be able to hear anything. If you unmute yourself and say something, you will not be heard.
You are able to hear other participants and they are able to hear you.
We'd appreciate if you all test if there are differences between in audio call quality in beta 2.5.4.
More info here: https://bugs.telegram.org/c/757/29.
PC 64bit // Windows 8.1 - 10