# ICU Plugin in 6.x

**URL:** <https://discuss.elastic.co/t/icu-plugin-in-6-x/108672>\
**Category:** Elasticsearch\
**Created:** [November 22, 2017, 8:37am UTC](https://discuss.elastic.co/t/icu-plugin-in-6-x/108672 "2017-11-22T08:37:10Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Zaid\_Amir](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zaid_amir/32/54679_2.png) [@Zaid\_Amir](https://discuss.elastic.co/u/Zaid_Amir)\
**Post date:** [November 22, 2017, 8:37am UTC](https://discuss.elastic.co/t/icu-plugin-in-6-x/108672/1 "2017-11-22T08:37:10Z")

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In the 6.x breaking changes documentation it's stated that indices created in the previous major version (i.e 5.x) need to be re-indexed in order to benefit from the changes to the ICU plugin. Referenced [here](https://www.elastic.co/guide/en/elasticsearch/reference/6.x/breaking_60_plugins_changes.html#_icu_analysis_plugin).

Am I reading this correctly? Is it a must to re-index if some fields use the ICU-Plugin? What happens to fields analyzed with ICU if I do not re-index?

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**Author:** ![Zaid\_Amir](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zaid_amir/32/54679_2.png) [@Zaid\_Amir](https://discuss.elastic.co/u/Zaid_Amir)\
**Post date:** [December 6, 2017, 11:53am UTC](https://discuss.elastic.co/t/icu-plugin-in-6-x/108672/2 "2017-12-06T11:53:28Z")

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Anyone can shed some light on this?

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**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\
**Post date:** [December 6, 2017, 1:44pm UTC](https://discuss.elastic.co/t/icu-plugin-in-6-x/108672/3 "2017-12-06T13:44:43Z")

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I guess what written there says that you need to reindex indeed. @jimczi might tell more.

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**Author:** ![Zaid\_Amir](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/zaid_amir/32/54679_2.png) [@Zaid\_Amir](https://discuss.elastic.co/u/Zaid_Amir)\
**Post date:** [December 7, 2017, 6:43am UTC](https://discuss.elastic.co/t/icu-plugin-in-6-x/108672/4 "2017-12-07T06:43:00Z")

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I am not keen on re-indexing again this year, just did that last year and my indices have grown 10 folds since I last re-indexed so I really wanna postpone this til ES 7.X.

What I want to know is what to expect when I don't re-index. It says and I quote "_Indices created in the previous major version will need to be reindexed in order to return correct (and correctly ordered) results_"

What does it mean by incorrect results? Is it related to character folding?

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [January 4, 2018, 6:43am UTC](https://discuss.elastic.co/t/icu-plugin-in-6-x/108672/5 "2018-01-04T06:43:25Z")

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