Readr 3.3.1: Readr Voice is the only voice you hear.

• The first time you listen, Readr waits for Readr Voice instead of
  reading in an Apple voice meanwhile — the Listen bar shows the one-time
  download's progress, and the book starts the moment the voice is ready
• Readr Voice keeps reading with the screen locked. It reads ahead while
  the app is open (an hour, or the rest of the book while charging) and
  plays from that with the phone in your pocket; if it ever runs out, it
  pauses and asks you to unlock rather than switching voices
• Speed changes no longer restart the sentence
• The voice menu is Readr Voice, with Apple's voices a tap away under
  "Other voices" for anyone who prefers them; books in other languages
  keep Apple's voices as before
• If the download can't finish, the bar says so with a Retry — no
  surprise voice