Ruby versions: "required" vs "preferred"

I know that I can find out the minimum Ruby version required for a Rails project by looking at rails.gemspec file.

For some Rails versions, the required Ruby version is mentioned in the Release Notes. (I really cannot understand why something fundamental like the minimum Ruby version required is not listed in each and every Release Note or in some dedicated documentation page?!)

Anyway, the 7.0 Release Notes also mention a “preferred” Ruby version (“Ruby 2.7.0+ required, Ruby 3.0+ preferred”).

So my questions are:

  • What does it mean that a Ruby version is “preferred”?
  • In case the “preferred” Ruby version is not mentioned, does it mean it is the same as in the last previous release which mentions the “preferred” version?