This section discusses the changes that you need to be aware of when migrating your application to Elasticsearch 6.6.
Using automatically expanded fields for the "all fields" mode ("default_field": "*")
simple_query_string now raises a warning and
a deprecation notice to be logged for queries beyond a certain number of fields. This limit
will be enforced with a hard error starting in 7.0 and is determined by the
indices.query.bool.max_clause_count setting which defaults to 1024.
_source_include URL Parametersedit
_source_include are deprecated in favor of
_source_includes because those line up better with the
rest of Elasticsearc’s APIs and Elasticsearch will raise a deprecation warning
if those are used on any APIs. We plan to drop support for
_source_include in 7.0.