anchor.diff:  with each update, deletes included. Optionally, the version number can be
   set to an external value (for example, if maintained in a
   database). To enable this functionality, `version_type` should be set to
  -`external`. The value provided must be a numeric, long value greater or equal to 0,
  +`external`. The value provided must be a numeric, long value greater than or equal to 0,
   and less than around 9.2e+18. 
   
   When using the external version type, the system checks to see if
  
positive.code: // CONSOLE
  // TEST[continued]
  
  *NOTE:* versioning is completely real time, and is not affected by the
  near real time aspects of search operations. If no version is provided,
  then the operation is executed without any version checks.
  
  
negative.code: also supports other types for specific use cases. Here is an overview of
  the different version types and their semantics.
  
  `internal`:: Only index the document if the given version is identical to the version
  of the stored document.
  deprecated[6.7.0, Please use `if_seq_no` & `if_primary_term` instead. See <<optimistic-concurrency-control>> for more details.]
  
  
  `external` or `external_gt`:: Only index the document if the given version is strictly higher
  than the version of the stored document *or* if there is no existing document. The given
  version will be used as the new version and will be stored with the new document. The supplied
  version must be a non-negative long number.
  
  `external_gte`:: Only index the document if the given version is *equal* or higher
  than the version of the stored document. If there is no existing document
  the operation will succeed as well. The given version will be used as the new version
  and will be stored with the new document. The supplied version must be a non-negative long number.
  