I can't seem to get rancher-compose upgrade to work as per the docs

I have a simple service with the docker-compose.yml like this:

cmm-frontend:
image: docker.pibenchmark.com/cmm-frontend:150915
ports:
- "8888:80/tcp"
environment:
REST_HOST: xxxxxx.pibenchmark.com
REST_PORT: 8088

now I wish to bump the version so I tried this:

cmm-frontend:
cmm-frontend-170915:
image: docker.pibenchmark.com/cmm-frontend:170915
ports:
- "8888:80/tcp"
environment:
REST_HOST: xxxxxx.pibenchmark.com
REST_PORT: 8088

Running this creates a new stack cmm-upgrade and a single service cmm-frontend-170915 with no containers then fails:

[kevin@kev-test cmm-upgrade]$ rancher-compose upgrade cmm-frontend cmm-frontend-170915
INFO[0000] Creating environment cmm-upgrade
INFO[0000] Creating service cmm-frontend-170915
FATA[0000] Failed to find service cmm-frontend

I’m obviously missing something here. How can I specify the stack to upgrade?

You pass in -p <stack_name> before the upgrade to indicate the stack.

Thanks, that all works like a dream.