IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
Also see Breaking changes in 7.1.
Indices created in 6.x with
date_nanosfields using formats that are incompatible with java.time patterns will cause parsing errors, incorrect date calculations or wrong search results. https://github.com/elastic/elasticsearch/pull/52555 This is fixed in Elasticsearch 7.7 and later versions.