# Difference between \_version and \[\_seq\_no, \_primary\_term\]
**URL:** https://discuss.elastic.co/t/difference-between-version-and-seq-no-primary-term/182859
**Category:** Elasticsearch
**Created:** [May 27, 2019, 8:13am UTC](https://discuss.elastic.co/t/difference-between-version-and-seq-no-primary-term/182859 "2019-05-27T08:13:25Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@shayantabrizi](https://discuss.elastic.co/u/shayantabrizi)
#### Post date: [May 27, 2019, 8:13am UTC](https://discuss.elastic.co/t/difference-between-version-and-seq-no-primary-term/182859/1 "2019-05-27T08:13:25Z")
It seems to me that both versioning (\_version; See [here](https://www.elastic.co/blog/elasticsearch-versioning-support)) and [\_seq\_no, \_primary\_term] (See [here)](https://www.elastic.co/guide/en/elasticsearch/reference/current/optimistic-concurrency-control.html) are used for optimistic concurrency control (e.g., to determine the version of a document we want to update). What's the difference between them and when should we use each?
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### Author:  [@DavidTurner](https://discuss.elastic.co/u/DavidTurner)
#### Post date: [May 27, 2019, 8:21am UTC](https://discuss.elastic.co/t/difference-between-version-and-seq-no-primary-term/182859/2 "2019-05-27T08:21:24Z")
[You should use `_seq_no` and `_primary_term`.](https://github.com/elastic/elasticsearch/issues/19269#issuecomment-488598561)
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [June 24, 2019, 8:21am UTC](https://discuss.elastic.co/t/difference-between-version-and-seq-no-primary-term/182859/3 "2019-06-24T08:21:32Z")
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