BzrDir.create always creates the default format, not one of <class 'bzrlib.bzrdir.BzrDirMeta1'>

Attempting to perform a push_and_update on a branch towards a remove server where we keep a copy of the development, we did hit this error message.
Note: we hadn't used push_and_update since mid 2013, but it used to work nicely until then, at least.
Using Ubuntu 14.04 in the desktop computer where the command was launched.
Push command works as expected.

=========================

Run command: bzr push-and-update bzr+ssh://<email address hidden>/path/ourproject/
bzr: ERROR: exceptions.AssertionError: BzrDir.create always creates the default format, not one of <class 'bzrlib.bzrdir.BzrDirMeta1'>

Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 930, in exception_to_return_code
    return the_callable(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 1121, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 673, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 697, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/qbzr/lib/commands.py", line 829, in run
    return run_subprocess_command(cmd, bencoded)
  File "/usr/lib/python2.7/dist-packages/bzrlib/plugins/qbzr/lib/subprocess.py", line 1034, in run_subprocess_command
    return commands.run_bzr(argv)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 1121, in run_bzr
    ret = run(*run_argv)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 673, in run_argv_aliases
    return self.run(**all_cmd_args)
  File "/usr/lib/python2.7/dist-packages/bzrlib/commands.py", line 697, in run
    return self._operation.run_simple(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 136, in run_simple
    self.cleanups, self.func, *args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/bzrlib/cleanup.py", line 166, in _do_with_cleanups
    result = func(*args, **kwargs)
  File "/home/xavi/.bazaar/plugins/push_and_update/__init__.py", line 51, in run
    return push_and_update_helper(location=location)
  File "/home/xavi/.bazaar/plugins/push_and_update/push_and_update.py", line 46, in push_and_update_helper
    _push_and_update(local_branch, location)
  File "/home/xavi/.bazaar/plugins/push_and_update/push_and_update.py", line 62, in _push_and_update
    target_branch = _get_target_branch(local_branch, location)
  File "/home/xavi/.bazaar/plugins/push_and_update/push_and_update.py", line 57, in _get_target_branch
    target_branch = local_branch.bzrdir.create_branch_and_repo(location)
  File "/usr/lib/python2.7/dist-packages/bzrlib/controldir.py", line 604, in create_branch_and_repo
    controldir = klass.create(base, format)
  File "/usr/lib/python2.7/dist-packages/bzrlib/bzrdir.py", line 780, in create
    "default format, not one of %r" % cls)
AssertionError: BzrDir.create always creates the default format, not one of <class 'bzrlib.bzrdir.BzrDirMeta1'>

bzr 2.7.0dev1 on python 2.7.6 (Linux-3.16.0-53-generic-x86_64-with-
    Ubuntu-14.04-trusty)
Updating location: bzr+ssh://<email address hidden>/path/ourproject/
arguments: ['/usr/bin/bzr', 'qsubprocess', '--bencode', 'l15:push-and-
    update49:bzr+ssh://<email address hidden>/path/ourproject/e']
plugins: bash_completion[2.7.0dev1], changelog_merge[2.7.0dev1],
    explorer[1.3.0], fastimport[0.14.0dev], grep[2.7.0dev1],
    launchpad[2.7.0dev1], netrc_credential_store[2.7.0dev1],
    news_merge[2.7.0dev1], po_merge[2.7.0dev1], push_and_update[0.2.0dev],
    qbzr[0.23.1], weave_fmt[2.7.0dev1]
encoding: 'utf-8', fsenc: 'UTF-8', lang: 'ca_ES.UTF-8'

*** Bazaar has encountered an internal error. This probably indicates a
    bug in Bazaar. You can help us fix it by filing a bug report at
        https://bugs.launchpad.net/bzr/+filebug
    including this traceback and a description of the problem.