code: function markVersions(instances) {
          let highestVersion = '0.0.0';
          let instance;
  
          Object.keys(instances).forEach((instanceId) => {
              instance = instances[instanceId];
              if (instance.version && util.versionCompare(instance.version, highestVersion) > 0) {
                  highestVersion = instance.version;
              }
          });
  
          Object.keys(instances).forEach((instanceId) => {
              instance = instances[instanceId];
              if (!instance.version || util.versionCompare(instance.version, highestVersion) === 0) {
                  instance.versionOk = true;
              } else {
                  instance.versionOk = false;
              }
          });
      }
docs: Checks that master instance has the most recent
  version of all the BIG-IP instances
  
  @param {Object} instances - Instances map