This section discusses the changes that you need to be aware of when migrating your application to {es} 8.18.
See also [release-highlights] and [es-release-notes].
coming::[8.18.0]
The following changes in {es} 8.18 might affect your applications and prevent them from operating normally. Before upgrading to 8.18, review these changes and take the described steps to mitigate the impact.
Change Semantic Text To Act Like A Normal Text Field
Details
The previous semantic_text format used a complex subfield structure in _source to store the embeddings. This complicated interactions/integrations with semantic_text fields and _source in general. This new semantic_text format treats it as a normal text field, where the field’s value in _source is the value assigned by the user.
Impact
Users who parsed the subfield structure of the previous semantic_text format in _source will need to update their parsing logic. The new format does not directly expose the chunks and embeddings generated from the input text. The new format will be applied to all new indices, any existing indices will continue to use the previous format.
Drop TLS_RSA cipher support for JDK 24
Details
This change removes TLS_RSA ciphers from the list of default supported ciphers, for Elasticsearch deployments running on JDK 24.
Impact
The dropped ciphers are TLS_RSA_WITH_AES_256_GCM_SHA384, TLS_RSA_WITH_AES_128_GCM_SHA256, TLS_RSA_WITH_AES_256_CBC_SHA256, TLS_RSA_WITH_AES_128_CBC_SHA256, TLS_RSA_WITH_AES_256_CBC_SHA, and TLS_RSA_WITH_AES_128_CBC_SHA. TLS connections to Elasticsearch using these ciphers will no longer work. Please configure your clients to use one of supported cipher suites.
Disable machine learning on macOS x86_64
Details
The machine learning plugin is permanently disabled on macOS x86_64. For the last three years Apple has been selling hardware based on the arm64 architecture, and support will increasingly focus on this architecture in the future. Changes to upstream dependencies of Elastic’s machine learning functionality have made it unviable for Elastic to continue to build machine learning on macOS x86_64.
Impact
To continue to use machine learning functionality on macOS please switch to an arm64 machine (Apple silicon). Alternatively, it will still be possible to run Elasticsearch with machine learning enabled in a Docker container on macOS x86_64.
Set allow_partial_search_results=true by default
Details
Before this change, in case of shard failures, EQL queries always returned an error. With this change, they will keep running and will return partial results.
Impact
EQL queries that would previously fail due to shard failures, will now succeed and return partial results. The previous defaults can be restored by setting xpack.eql.default_allow_partial_results cluster setting to false or setting with allow_partial_search_results to false in the query request.
The following functionality has been deprecated in {es} 8.18 and will be removed in a future version. While this won’t have an immediate impact on your applications, we strongly encourage you to take the described steps to update your code after upgrading to 8.18.
To find out if you are using any deprecated functionality, enable deprecation logging.
Increase the frozen indices deprecation level to CRITICAL
Details
The migration deprecations API previously returned a warning on frozen indices. Support for reading frozen indices will be removed in 9.0, so in 8.18 this has been made a critical issue.
Impact
Users are required to unfreeze any frozen indices before upgrading to 9.x. (N.B. It was impossible to freeze indices in 8.x, so this only applies to 7.x indices which have not been reindexed.)
Deprecate ability to connect to nodes of versions 8.17 and earlier
Details
Versions 9.0.0 and later of {es} will not support communication with nodes of versions earlier than 8.18.0, so the ability to connect to nodes of earlier versions is deprecated in this version. This applies both to communication within a cluster and communication across clusters (e.g. for {ccs} or {ccr}).
{es} will report in its deprecation logging each time it opens a connection to a node that will not be supported from version 9.0.0 onwards. You must upgrade all your clusters to version 8.18.0 or later before upgrading any of your clusters to 9.0.0 or later.
Impact
Upgrade all of your clusters to at least 8.18.0 before upgrading any of them to 9.0.0 or later.
V_7 deprecation logging set to critical
Details
This changes the V_7 API deprecation logging level to CRITICAL.
Impact
Any usage of deprecated V_7 API features will now be logged at the CRITICAL level. This does not change functionality.