Breaking changes in 7.6

This section discusses the changes that you need to be aware of when migrating your application to Elasticsearch 7.6.

See also What’s new in 7.15 and Release notes.

If you use an API key to create another API key (sometimes called a derived key), its behavior is impacted by the fix for CVE-2020-7009.

When you make a request to create API keys, you can specify an expiration and privileges for the API key. Previously, when you created a derived key, it had no privileges. This behavior disregarded any privileges that you specified in the create API key API.

As of 7.6.2, this behavior changes. To create a derived key, you must explicitly specify a role descriptor with no privileges:

...
"role_descriptors": {
    "no-privilege": {
    }
}
...

It’s possible to aggregate and sort on the built-in _id field by loading an expensive data structure called fielddata. This was deprecated in 7.6 and will be disallowed by default in 8.0. As an alternative, the _id field’s contents can be duplicated into another field with docvalues enabled (note that this does not apply to auto-generated IDs).

The sparse_vector field type has been deprecated and will be removed in 8.0. We have not seen much interest in this experimental field type, and don’t see a clear use case as it’s currently designed. If you have feedback or suggestions around sparse vector functionality, please let us know through GitHub or the discuss forums.

The vector functions of the form function(query, doc['field']) are deprecated, and the form function(query, 'field') should be used instead. For example, cosineSimilarity(query, doc['field']) is replaced by cosineSimilarity(query, 'field').

The nGram and edgeNGram tokenizer names haven been deprecated with 7.6. Mappings for indices created after 7.6 will continue to work but emit a deprecation warning. The tokenizer name should be changed to the fully equivalent ngram or edge_ngram names for new indices and in index templates.