juju status 1.17.0 quietly fails with 1.6.x agents

[Curtis Hovey]

Using juju 1.17.0 to get the status of an env running 1.16.5 agents, I cannot see any services or units. I can see which machine instances are running, but nothing else about the machine.

$ juju status
environment: ""
machines:
  "0":
    instance-id: 9e78c52b-90d7-4360-bb02-78da71869df3
  "1":
    instance-id: a98fe254-92bf-40e7-8c7e-fa39c30b2f1e
  "2":
    instance-id: e9f70597-28c0-470a-9367-9f27b28e5b42
  "3":
    instance-id: daf0e9a8-55e2-4953-a92e-d1018789a47c
  "4":
    instance-id: c50544b0-46dc-4035-beab-37383714db09
  "5":
    instance-id: 6ec631d9-728f-4fe1-9f58-6ae7e947caaa
services: {}