Same with me too! I suspect it might be a bug with the release. Logs are as follows:
Error during setup of component hassio
Traceback (most recent call last):
File "/usr/lib/python3.6/site-packages/homeassistant/setup.py", line 196, in _async_setup_component
result = yield from component.async_setup(hass, processed_config)
File "/usr/lib/python3.6/site-packages/homeassistant/components/hassio.py", line 172, in async_setup
if not (yield from hassio.is_connected()):
File "/usr/lib/python3.6/site-packages/homeassistant/components/hassio.py", line 262, in _wrapper
data = yield from funct(*argv, **kwargs)
File "/usr/lib/python3.6/site-packages/homeassistant/components/hassio.py", line 333, in send_command
X_HASSIO: os.environ.get('HASSIO_TOKEN')
File "/usr/lib/python3.6/site-packages/aiohttp/helpers.py", line 99, in __iter__
ret = yield from self._coro
File "/usr/lib/python3.6/site-packages/aiohttp/client.py", line 275, in _request
resp = req.send(conn)
File "/usr/lib/python3.6/site-packages/aiohttp/client_reqrep.py", line 463, in send
writer.write_headers(status_line, self.headers)
File "/usr/lib/python3.6/site-packages/aiohttp/http_writer.py", line 247, in write_headers
[k + SEP + v + END for k, v in headers.items()])
File "/usr/lib/python3.6/site-packages/aiohttp/http_writer.py", line 247, in <listcomp>
[k + SEP + v + END for k, v in headers.items()])
TypeError: must be str, not NoneType