Es gibt wohl 2 Varianten.

Die Ältere:

1. Open portainer
2. Navigate to iobroker container
3. Click >Console
4. Click Connect
5. Stop iobroker daemon (-u is important in container)
   pkill -u iobroker
6. iobroker update
iobroker upgrade self
7. iobroker start

Die Neuere:

1. Open portainer
2. Navigate to iobroker container
3. Click >Console
4. Click Connect
5. Stop iobroker daemon
   maintenance on
6. iobroker update
iobroker upgrade self
7. maintenance off oder maintenance restart