# Only change date format on mapping with 6.X

**URL:** <https://discuss.elastic.co/t/only-change-date-format-on-mapping-with-6-x/155606>\
**Category:** Elasticsearch\
**Created:** [November 6, 2018, 7:38pm UTC](https://discuss.elastic.co/t/only-change-date-format-on-mapping-with-6-x/155606 "2018-11-06T19:38:54Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![toshi78](https://avatars.discourse-cdn.com/v4/letter/t/b5e925/32.png) [@toshi78](https://discuss.elastic.co/u/toshi78)\
**Post date:** [November 6, 2018, 7:38pm UTC](https://discuss.elastic.co/t/only-change-date-format-on-mapping-with-6-x/155606/1 "2018-11-06T19:38:54Z")

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Hi !

I've discovered that I need milisecond on a field with type `date`, however I already stored some data with it. On Elasticsearch 2.X, it was possible to only change the date format of a field:

> The `format` setting must have the same setting for fields of the same name in the same index. Its value can be updated on existing fields using the [PUT mapping API](https://www.elastic.co/guide/en/elasticsearch/reference/2.0/indices-put-mapping.html).

> **[Put Mapping | Elasticsearch Guide \[2.0\] | Elastic](https://www.elastic.co/guide/en/elasticsearch/reference/2.0/indices-put-mapping.html)**

However, I don't see anything on the Elasticsearch 6.X documentation, and I only need to change the following:

> "format" : "yyyy-MM-dd HH:mm:ssZ"

To:

> "format" : "yyyy-MM-dd HH:mm:ss.SSSSSSZ"

Is the modification's possible without consequences ?

Many thanks 🙂

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [December 4, 2018, 7:38pm UTC](https://discuss.elastic.co/t/only-change-date-format-on-mapping-with-6-x/155606/2 "2018-12-04T19:38:54Z")

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