# File lib/mixlib/authentication/signedheaderauth.rb, line 351
      def server_api_version
        key = (self[:headers] || {}).keys.select do |k|
          k.casecmp("x-ops-server-api-version") == 0
        end.first
        if key
          self[:headers][key]
        else
          DEFAULT_SERVER_API_VERSION
        end
      end