discourse/app/models/discourse_version_check.rb

class DiscourseVersionCheck
  if rails4?
    include ActiveModel::Model
  else
    include ActiveAttr::Attributes
    include ActiveAttr::MassAssignment
    include ActiveModel::Serialization
  end

  attr_accessor :latest_version, :critical_updates, :installed_version, :installed_sha, :missing_versions_count, :updated_at, :version_check_pending

  unless rails4?
    def active_model_serializer
      DiscourseVersionCheckSerializer
    end
  end
end