Comment 54 for bug 1855736

The previous error is in command line.
In command line the 0.8.21 work, but not with deja-dup it is the error :
Traceback (innermost last):
  File "/usr/bin/duplicity", line 92, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 75, in with_tempdir
    fn()
  File "/usr/lib/python3/dist-packages/duplicity/dup_main.py", line 1555, in main
    action = commandline.ProcessCommandLine(sys.argv[1:])
  File "/usr/lib/python3/dist-packages/duplicity/commandline.py", line 1223, in ProcessCommandLine
    config.backend = backend.get_backend(args[0])
  File "/usr/lib/python3/dist-packages/duplicity/backend.py", line 223, in get_backend
    obj = get_backend_object(url_string)
  File "/usr/lib/python3/dist-packages/duplicity/backend.py", line 209, in get_backend_object
    return factory(pu)
  File "/usr/lib/python3/dist-packages/duplicity/backends/giobackend.py", line 82, in __init__
    ensure_dbus()
  File "/usr/lib/python3/dist-packages/duplicity/backends/giobackend.py", line 37, in ensure_dbus
    output = p.communicate()[0].decode("utf8", errors="replace")
 AttributeError: 'str' object has no attribute 'decode'

I have found solution for the 0.8.21 version :

Don't use sudo but su and after launch deja-dup !

So I keep this version :)