Version 8.13.1 of the Elastic Stack was released today. We recommend you upgrade to this latest version. We recommend 8.13.1 over the previous version 8.13.0.
The 8.13.1 patch release contains a fix for a bug in the 8.13 release. The bug affects clusters running 8.10+ that either have an active downsampling configuration or have used downsampling since upgrading to version 8.10+. It causes clusters to fail upgrading to 8.13.0, as Elasticse