Tag notifications like "moved" "opened" or "too hot" on the Android app are configured by default to use "speech", which makes the phone announce the event by human voice even when the app is not open or running. Some users absolutely loved it, while others really hated it when it fires off unexpectedly during meeting or in the middle of night.
There are three different volumes in Android namely "Music", "Alarm" and "Notification". You have to mute the "notification" volume to mute this announcement, which was not immediately obvious to many people. Besides, this also turns off other important audible notifications. Another way was to check off the "Use speech" box inside the app interface for each tag / type of monitoring individually, but you had to remember which tag had which monitoring enabled that may produce the sound, and check off one by one.
Now with Android 8, the Android app version 2.17.5 and above allows you to turn on/off any sound for each category of events like below (open Android system Settings -> Apps & notifications -> Notifications -> App notifications -> WirelessTag)
Configuration for the category of events you have never received before will not be displayed, so on your device the screen may have fewer lines than the above.
This must have been a much awaited feature for all Android users, and should have been implemented a long time ago. Please share your feedback using the comment button.