OpenSearch provides clients for several popular programming languages, with more coming. In general, clients are compatible with clusters running the same major version of OpenSearch (`major.minor.patch`).
For example, a 1.0.0 client works with an OpenSearch 1.1.0 cluster, but might not support any non-breaking API changes in OpenSearch 1.1.0. A 1.2.0 client works with the same cluster, but might allow you to pass unsupported options in certain functions. We recommend using the same version for both, but if your tests pass after a cluster upgrade, you don't necessarily need to upgrade your clients immediately.
Most clients that work with Elasticsearch OSS 7.10.2 *should* work with OpenSearch, but the latest versions of those clients might include license or version checks that artificially break compatibility. This page includes recommendations around which versions of those clients to use for best compatibility with OpenSearch.
OpenSearch 2.0.0 no longer supports compatibility with legacy clients. Due to breaking changes with REST APIs, some features are not supported when using OpenSearch 1.x clients to connect to OpenSearch 2.0.
If you test a legacy client and verify that it works, please [submit a PR](https://github.com/opensearch-project/documentation-website/pulls) and add it to this table.