Ошибка обновления до django 1.11.12 в models / manager.py serve_to_class

Я давно не касался проекта и понял, что обновил свой django до версии 1.11.12. Попытка перезапустить проект (сервер запуска) и обнаружила несколько устаревших пакетов (easy-эскизы и psycopg2). Запустил pip install upgrade на тех. Теперь, когда я бегу, я получаю следующую ошибку, и кажется, что она исходит от моих моделей? Не знаю, о чем он мне говорит, или о правильном порядке действий. Может быть, я пропустил еще один этап обновления, когда перешел на django 1.11? (извините, прошло много времени с тех пор, как я коснулся этого кода)

Unhandled exception in thread started by <function wrapper at 0x104ab2500>
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/django/utils/autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/django/core/management/commands/runserver.py", line 116, in inner_run
    autoreload.raise_last_exception()
  File "/usr/local/lib/python2.7/site-packages/django/utils/autoreload.py", line 251, in raise_last_exception
    six.reraise(*_exception)
  File "/usr/local/lib/python2.7/site-packages/django/utils/autoreload.py", line 228, in wrapper
    fn(*args, **kwargs)
  File "/usr/local/lib/python2.7/site-packages/django/__init__.py", line 27, in setup
    apps.populate(settings.INSTALLED_APPS)
  File "/usr/local/lib/python2.7/site-packages/django/apps/registry.py", line 108, in populate
    app_config.import_models()
  File "/usr/local/lib/python2.7/site-packages/django/apps/config.py", line 202, in import_models
    self.models_module = import_module(models_module_name)
  File "/usr/local/Cellar/python/2.7.11/Frameworks/Python.framework/Versions/2.7/lib/python2.7/importlib/__init__.py", line 37, in import_module
    __import__(name)
  File "/Users/shane.thomas/programming/sw_nga_site/swsite/models.py", line 12, in <module>
    from filer.fields.image import FilerImageField
  File "/usr/local/lib/python2.7/site-packages/filer/fields/image.py", line 4, in <module>
    from ..models import Image
  File "/usr/local/lib/python2.7/site-packages/filer/models/__init__.py", line 3, in <module>
    from .clipboardmodels import *  # flake8: noqa
  File "/usr/local/lib/python2.7/site-packages/filer/models/clipboardmodels.py", line 9, in <module>
    from . import filemodels
  File "/usr/local/lib/python2.7/site-packages/filer/models/filemodels.py", line 18, in <module>
    from .foldermodels import Folder
  File "/usr/local/lib/python2.7/site-packages/filer/models/foldermodels.py", line 240, in <module>
    mptt.register(Folder)
  File "/usr/local/lib/python2.7/site-packages/mptt/__init__.py", line 12, in register
    from mptt.models import MPTTModelBase
  File "/usr/local/lib/python2.7/site-packages/mptt/models.py", line 379, in <module>
    class MPTTModel(six.with_metaclass(MPTTModelBase, models.Model)):
  File "/usr/local/lib/python2.7/site-packages/django/utils/six.py", line 808, in __new__
    return meta(name, bases, d)
  File "/usr/local/lib/python2.7/site-packages/mptt/models.py", line 262, in __new__
    cls = super_new(meta, class_name, bases, class_dict)
  File "/usr/local/lib/python2.7/site-packages/django/db/models/base.py", line 162, in __new__
    new_class.add_to_class(obj_name, obj)
  File "/usr/local/lib/python2.7/site-packages/django/db/models/base.py", line 325, in add_to_class
    value.contribute_to_class(cls, name)
  File "/usr/local/lib/python2.7/site-packages/mptt/managers.py", line 81, in contribute_to_class
    super(TreeManager, self).contribute_to_class(model, name)
  File "/usr/local/lib/python2.7/site-packages/django/db/models/manager.py", line 120, in contribute_to_class
    setattr(model, name, ManagerDescriptor(self))
AttributeError: can't set attribute