# Working with multiple Nest version - JsonNetSerializer doesn't exist in Nest6

**URL:** <https://discuss.elastic.co/t/working-with-multiple-nest-version-jsonnetserializer-doesnt-exist-in-nest6/307255>\
**Category:** Elasticsearch\
**Tags:** language-clients\
**Created:** [June 15, 2022, 10:53am UTC](https://discuss.elastic.co/t/working-with-multiple-nest-version-jsonnetserializer-doesnt-exist-in-nest6/307255 "2022-06-15T10:53:52Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![Aharon\_Ya](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/aharon_ya/32/105769_2.png) [@Aharon\_Ya](https://discuss.elastic.co/u/Aharon_Ya)\
**Post date:** [June 15, 2022, 10:53am UTC](https://discuss.elastic.co/t/working-with-multiple-nest-version-jsonnetserializer-doesnt-exist-in-nest6/307255/1 "2022-06-15T10:53:52Z")

</div>

Hello Team,  
We are working on upgrading our Elastic from 5.x to the latest.  
Currently, we are working against them both (as a rollout process). I'm trying to use multiple Nest versions as guided here: [https://www.elastic.co/blog/nest-and-elasticsearch-net-upgrading-your-codebase](https://www.elastic.co/blog/nest-and-elasticsearch-net-upgrading-your-codebase), but I have a problem using the `JsonNetSerializer` and `JsonSerializerSettings` as they do not exist under `Nest6` or under `Elasticsearch.Net6`. Is there any Idea how we can deal with it?  
This is the code I'm trying but doesn't compile:

```auto
Elasticsearch.Net6.SingleNodeConnectionPool pool = new Elasticsearch.Net6.SingleNodeConnectionPool(new Uri(url));

            Nest6.ConnectionSettings connectionSettings = new Nest6.ConnectionSettings(
              pool,
              sourceSerializer: (builtin, settings) =>
                  new JsonNetSerializer(
                      builtin,
                      settings,
                      () => new JsonSerializerSettings { NullValueHandling = NullValueHandling.Ignore })
            );

```

Thanks!

---

<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:** [July 13, 2022, 10:54am UTC](https://discuss.elastic.co/t/working-with-multiple-nest-version-jsonnetserializer-doesnt-exist-in-nest6/307255/2 "2022-07-13T10:54:33Z")

</div>

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