Is Codeigniter 3 php 7 ready?

Narf, you miss the point.
The point is not what you did, but whether users know it.

I'm not missing the point, I'm just tired of having to tell people that the Earth is round ...

5.4+ means "5.4 and everything above it", which includes 7 as well - that's basic logic/math. If somebody needs to be explicitly told that 7 is a larger number than 5.4, then quite frankly I'd rather not have them in the CI community.