This section discusses the changes that you need to be aware of when migrating your application to Elasticsearch 7.5.
Stricter checking for wildcard queries on _indexedit
Previously, a wildcard query on the
_index field matched directly against the
fully-qualified index name. Now, in order to match against remote indices like
i`cluster:index`, the query must contain a colon, as in
behavior aligns with the way indices are matched in the search endpoint.