Assert the version of the CMS: "be" compares the whole version ("5.1.3"), "start with" a version line by whole parts ("5" or "5.1"). The version is the one the toolbar reports, so the step needs a logged-in staff user on a CMS page.
Examples
Then the CMS version should start with "5"
Then the CMS version should start with "5.1"
And the CMS version should be "5.1.3"
Then the CMS version should not start with "3"
But the CMS version should not be "4.1.0"
Pattern
Then(/^the CMS version should( not)* (be|start with) "([^"]*)"$/, …)
Part of @webship-js/django-cms-steps (github.com/webship/django-cms-steps), a step pack for Webship-js 2.0.x.