Legejo 1.20.2

• The app holds when the server is down, not only the network. With the
  network there but the server behind it down, the app installed on a phone
  showed an error, or asked you to log in, and "Books on this device" did
  nothing. Now it opens on the books saved on the device, as it does without
  a network, and finds its way back once the server answers again.
• On a poor connection just after an upgrade, the app no longer mixes the
  page of the new version with the files of the old one, which made every
  page change fail. What could not be fetched is called that, not an
  internal error, and the links on the error page always do something.
• Upgrading: nothing to do. The app on a phone takes the change the next
  time it is opened with the server in reach.