CHANGES mentions dropped ruby 2.4.0 support (#666)
CHANGES mentions dropped ruby 2.4.0 support (#666)

Drop of ruby 2.3.0 was already mentioned in CHANGES.md.  Drop of 2.4.0 was not, but 2.4.0 is in fact dropped in http release 5.0.0, and it should also be mentioned in changelog.
httprb/http.rb,httprb/http