Walkie Talkie settings, on the website and in the Magpie app, have a new Live talk row under Talking. It is on, as before.
Turned off, conversations have no Live switch: your messages are sent when you let go, with Undo, and when other people talk live, their message arrives as a recording to play once they finish. Turning it on again brings back each conversation's Live as you left it.
The first steps on the Walkie Talkie page end with Live talk too, with Turn off. In Personal they are now titled Get started.