Because:

• Elastic stopped supporting Elasticsearch 6.x more than a year ago, on Feb 10, 2022 (source)
• It’s been so long since Elasticsearch 5.x stopped being supported that I can’t even find the date
• People wanting to stick to older Elasticsearch versions can stick to older Hibernate Search versions (Hibernate Search 6.2)
• Testing many versions of Elasticsearch has a cost: both financially (AWS EC2 costs) and operationally (builds take much longer)

We’ll need to:

• Adapt the dialect factory and tests
• Remove now-unnecessary dialects and the resulting dead code, e.g. Elasticsearch56WorkFactory or org.hibernate.search.backend.elasticsearch.work.impl.SearchWork.Builder#forElasticsearch62AndBelow
• Remove now-unnecessary testing conditions (e.g. org.hibernate.search.util.impl.integrationtest.backend.elasticsearch.dialect.ElasticsearchTestDialect#isEmptyMappingPossible or org.hibernate.search.integrationtest.backend.elasticsearch.testsupport.util.ElasticsearchTckBackendFeatures#geoPointIndexNullAs)
• Remove mentions of older versions in the documentation
• Remove Elasticsearch 5.x/6.x environments from our Jenkinsfiles