Install fails for Unifi rockon

When I attempt the install the unifi rockon I get this error repeatedly in the log

/opt/rockstor/var/log/supervisord_ztask-daemon_stderr.log

Traceback (most recent call last):
File “/opt/rockstor/eggs/django_ztask-0.1.5-py2.7.egg/django_ztask/management/commands/ztaskd.py”, line 114, in _call_function
import(module_name)
File “/opt/rockstor/src/rockstor/storageadmin/views/init.py”, line 23, in
from disk import (DiskMixin, DiskListView, DiskDetailView) # noqa F401
File “/opt/rockstor/src/rockstor/storageadmin/views/disk.py”, line 30, in
from system import smart
File “/opt/rockstor/src/rockstor/system/smart.py”, line 20, in
from osi import run_command, get_base_device_byid, get_device_path
ImportError: cannot import name get_device_path
INFO:ztaskd:Calling storageadmin.views.rockon_helpers.install
ERROR:ztaskd:Error calling storageadmin.views.rockon_helpers.install. Details:
cannot import name get_device_path
WARNING:py.warnings:/opt/rockstor/eggs/Django-1.8.16-py2.7.egg/django/db/models/fields/init.py:1474: RuntimeWarning: DateTimeField Task.failed received a naive datetime (2018-04-05 22:54:32.767968) while time zone support is active.
RuntimeWarning)

any ideas what is happening?