Throat exception, peewee 3.9.4+

Traceback (most recent call last):
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/app.py", line 2295, in wsgi_app
    response = self.handle_exception(e)
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/app.py", line 1741, in handle_exception
    reraise(exc_type, exc_value, tb)
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/app.py", line 2292, in wsgi_app
    response = self.full_dispatch_request()
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/app.py", line 1815, in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/app.py", line 1718, in handle_user_exception
    reraise(exc_type, exc_value, tb)
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/_compat.py", line 35, in reraise
    raise value
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/app.py", line 1813, in full_dispatch_request
    rv = self.dispatch_request()
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/flask/app.py", line 1799, in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "/home/app/throat/app/__init__.py", line 1119, in login
    theuser = misc.load_user(user.uid)
  File "/home/app/throat/app/misc.py", line 970, in load_user
    user = user.join(Message, JOIN.LEFT_OUTER, on=((Message.receivedby == User.uid) & (Message.mtype != 6) & (Message.mtype != 9) & (Message.mtype != 41) & Message.read.is_null(True))).switch(User)
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/peewee.py", line 698, in inner
    method(clone, *args, **kwargs)
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/peewee.py", line 6645, in join
    on, attr, constructor = self._normalize_join(src, dest, on, attr)
  File "/home/app/.pyenv/versions/3.5.7/envs/app/lib/python3.5/site-packages/peewee.py", line 6572, in _normalize_join
    attr = fk_field.name
AttributeError: 'Expression' object has no attribute 'name'