# Backward compatibility while upgrding major version of elastic search
**URL:** https://discuss.elastic.co/t/backward-compatibility-while-upgrding-major-version-of-elastic-search/353858
**Category:** Elasticsearch
**Tags:** language-clients
**Created:** [February 22, 2024, 8:02am UTC](https://discuss.elastic.co/t/backward-compatibility-while-upgrding-major-version-of-elastic-search/353858 "2024-02-22T08:02:07Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@abhadauria](https://discuss.elastic.co/u/abhadauria)
#### Post date: [February 22, 2024, 8:02am UTC](https://discuss.elastic.co/t/backward-compatibility-while-upgrding-major-version-of-elastic-search/353858/1 "2024-02-22T08:02:07Z")
We are upgrading the major version of Elasticsearch from 7.x to 8.x, is there any guideline/documentation for the same as there are no changes for the same in NEST client for this version upgrade but there are changes in the ES clients which we are using to interact with ES from .NET application.
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### Author:  [@flobernd](https://discuss.elastic.co/u/flobernd)
#### Post date: [February 22, 2024, 9:01am UTC](https://discuss.elastic.co/t/backward-compatibility-while-upgrding-major-version-of-elastic-search/353858/2 "2024-02-22T09:01:45Z")
Hi!
We have a brief migration guide available here:
> **[Migration guide: From NEST v7 to .NET Client v8 | Elasticsearch .NET Client...](https://www.elastic.co/guide/en/elasticsearch/client/net-api/current/migration-guide.html)**
Please make sure the v8 client supports all the features you are currently using. NEST can be used with the ES8 server in compatibility mode for the time being. However, new ES8 functionality won't be supported that way.
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### Author:  [@abhadauria](https://discuss.elastic.co/u/abhadauria)
#### Post date: [February 22, 2024, 9:49am UTC](https://discuss.elastic.co/t/backward-compatibility-while-upgrding-major-version-of-elastic-search/353858/3 "2024-02-22T09:49:46Z")
thanks for responding @flobernd, we are continuing to use the NEST v7, however I am looking forward the required changes to have both the cluster in production with version 7.x and 8.x during upgrade, however I want to make sure that I can revert back to user 7.x if something breaks in 8.x after rolling out changes in production.
We have written few custom plugins to interact with ES server, we had to update those as per the new version of ES
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### Author:  [@flobernd](https://discuss.elastic.co/u/flobernd)
#### Post date: [February 22, 2024, 10:02am UTC](https://discuss.elastic.co/t/backward-compatibility-while-upgrding-major-version-of-elastic-search/353858/4 "2024-02-22T10:02:35Z")
@abhadauria For the client side, this might be useful to you:
> **[Connecting to Elasticsearch v8.x using the v7.17.x client | Elasticsearch...](https://www.elastic.co/guide/en/elasticsearch/client/net-api/7.17/connecting-to-elasticsearch-v8.html)**
For the server-side of things you should probably post in a different section of the community forums as I can't help you with that.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [March 21, 2024, 10:03am UTC](https://discuss.elastic.co/t/backward-compatibility-while-upgrding-major-version-of-elastic-search/353858/5 "2024-03-21T10:03:30Z")
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