First, the current version of SonarQube is 7.3 (7.4 imminent) and the current LTS. I start with this not just because it’s my favorite old saw, but because it’s really relevant to your question.
In fact, in more recent versions of SonarQube we’ve dropped
Why? Because nobody knows what to do with them; they’re not actionable. We kept “Complexity” but changed to its full name of “Cyclomatic Complexity”. It’s the total, aggregate cyclomatic complexity of all the files in your project.