As of OpenSearch 2.0 RC1, 1.x clients will stop working against 2.x because of API changes, and 2.x clients will not work against OpenSearch 1.x. This is inherited from ElasticSearch, and makes it very difficult to upgrade to major versions. Furthermore, we had introduced
opensearch.http.override_main_response_version, a version compatibility option that may need to be removed in OpenSearch 2.0 to prevent clients from breaking silently.
I’ve opened [PROPOSAL] Ensure clients are compatible across at least 2 major versions · Issue #17 · opensearch-project/opensearch-clients · GitHub and [BUG] Breaking changes with opensearch.http.override_main_response_version=true · Issue #3023 · opensearch-project/OpenSearch · GitHub, seeking feedback for both, please, on GitHub.