This section discusses the changes that you need to be aware of when migrating your application to Elasticsearch 7.12.
The following changes in Elasticsearch 7.12 might affect your applications and prevent them from operating normally. Before upgrading to 7.12, review these changes and take the described steps to mitigate the impact.
Breaking changes introduced in minor versions are normally limited to security and bug fixes. Significant changes in behavior are deprecated in a minor release and the old behavior is supported until the next major release. To find out if you are using any deprecated functionality, enable deprecation logging.
Force-merges on frozen and searchable snapshot indices will fail if merging is required.
In earlier versions a force-merge on a frozen index or a searchable snapshot index would incorrectly yield a successful response without performing the requested merge. This bug is fixed in version 7.12: from this version onwards a force-merge on these immutable indices will fail if the requested merge is not a no-op.
The search APIs
fields parameter returns fields inside
nested fields grouped together.
In earlier versions, fields retrieved via
fields in the search API were
returned as a flat list. From 7.12 on, fields inside an object that is mapped
nested field type are grouped together to maintain the independence of
each object inside the original nested array.