Email service@klett.de with proof of purchase (photo of your book + receipt). They will send you a private download link for the 2021 audio.
The Klett Augmented app allows downloading tracks for offline use. Open the app, go to “My Library”, select your Linie 1 B1 book, and tap “Download all audio”. This functions exactly as a native download. linie 1 b1 audio download 2021
If you don’t want to download, use the Klett Augmented App: Email service@klett