Elasticsearch has started migrating from AWS SDK for Java v1 to v2 due to the former reaching its end of support at the end of 2025. The transition to SDKv2 introduces several changes, including the requirement for specifying AWS regions, the exclusive use of IMDSv2 for instance metadata, and the adoption of full URL endpoints. Elasticsearch versions 8.19 and onwards, starting from 9.1.0, will incorporate SDKv2, with compatibility measures in place to minimize disruptions for users. The migration process involved extensive testing to handle differences between the SDK versions, with an emphasis on end-to-end tests that simulate real AWS API interactions. Users are advised to update their configurations where necessary, particularly concerning region specifications and endpoint URLs, and to conduct thorough tests on non-production clusters before applying changes in production environments.