OpenSearch legacy support can double compute cost

AWS extended patch coverage for specified legacy Elasticsearch and OpenSearch versions by 12 months, but from November 7, 2026 their support surcharge will equal the underlying instance price. The revised support schedule keeps those engines covered through November 7, 2027 and leaves storage charges unchanged. For teams running retrieval behind agents, this turns the discipline of benchmarking the full AWS stack into an upgrade deadline: price migration work against a potential doubling of instance spend rather than treating extended support as cheap insurance.