Elasticsearch version 8.13.1

When upgrading clusters from version 8.11.4 or earlier, if your cluster contains non-master-eligible nodes, information about the new functionality of these upgraded nodes may not be registered properly with the master node. This can lead to some new functionality added since 8.12.0 not being accessible on the upgraded cluster. If your cluster is running on ECK 2.12.1 and above, this may cause problems with finalizing the upgrade. To resolve this issue, perform a rolling restart on the non-master-eligible nodes once all Elasticsearch nodes are upgraded. This issue is fixed in 8.15.0.
The pytorch_inference process used to run Machine Learning models can consume large amounts of memory. In environments where the available memory is limited, the OS Out of Memory Killer will kill the pytorch_inference process to reclaim memory. This can cause inference requests to fail. Elasticsearch will automatically restart the pytorch_inference process after it is killed up to four times in 24 hours. (issue: #110530)

Searches involving nodes upgraded to 8.13.0 and a coordinator node that is running on version 8.12 or earlier can produce duplicate buckets when running date_histogram or histogram aggregations. This can happen during a rolling upgrade to 8.13 or while running cross-cluster searches. (issue: #108181).