JSON 1.8.3 incompatible

[LonghornRach]

I'm on Linux Fedora, using Ruby 2.5.1. (but no ruby version specified anyway) and rbenv. Looked at Issue 303 and so I installed 1.8.6. Then reran bundler to generate new gemfile.lock and everything looks fine for the moment...

An error occurred while installing json (1.8.3), and Bundler cannot
continue.                                                                    
Make sure that `gem install json -v '1.8.3' --source 'https://rubygems.org/'`
succeeds before bundling.                                                    

In Gemfile:
  rails was resolved to 4.2.3, which depends on
    actionmailer was resolved to 4.2.3, which depends on
      actionpack was resolved to 4.2.3, which depends on
        actionview was resolved to 4.2.3, which depends on
          rails-dom-testing was resolved to 1.0.7, which depends on
rails-deprecated_sanitizer was resolved to 1.0.3, which depends
on
              activesupport was resolved to 4.2.3, which depends on
                json

[LonghornRach]

edit: I've also had to update the rails gem to 4.2.10 to avoid a "stack level too deep" error