Elastic APM release notes

Review the changes, fixes, and more in each version of Elastic APM.

To check for security updates, go to Security announcements for the Elastic stack.

• Fix Fleet-managed apm-server hanging or crashing on config hot reload due to duplicate monitoring registry (#17872)

• Add config for tail-based sampling discard on write (#13950)
• Add config for tail-based sampling TTL (#16579)

• Truncate string slice attributes in OTLP labels (#434)
• Fix broken UI by explicitly enabling date detection for the system.process.cpu.start_time field (#130466)
• Use representative count for the event.success_count metric if available (#119995)
• Fix setting event.dataset to data_stream.dataset if event.dataset is empty, to have event.dataset in every logs-* data stream (#129074)
• Fix missing trusted root certificate authority in the docker image (#16928)

• Tail-based sampling: Fix missing or infrequent monitoring metric lsm_size and value_log_size (#17512)
• Fix default tracer http request sent to https endpoint error when both self-instrumentation and TLS are enabled (#17293)

• Tail-based sampling: Optimize performance for instances with more CPU and memory (#17254)

• Tail-based sampling: Fix ever-increasing dynamic group count monitoring metric (#17042)
• Tail-based sampling: Fix incorrectly large pebble database lsm_size monitoring metric in edge cases which causes TBS to be bypassed (#17149)
• Tail-based sampling: Log pubsub errors at error or warn level (#17135)

• Fix missing trusted root certificate authority in the docker image (#16928)

• Tail-based sampling: ignore subscriber position read error and proceed as if file does not exist to avoid crash looping (#16736)

• Tail-based sampling: Storage layer is rewritten to use Pebble database instead of BadgerDB. The new implementation offers a substantial throughput increase while consuming significantly less memory. Disk usage is significantly lower and more stable. See APM Transaction sampling docs for benchmark details. (#15235)

• Fix overflow in validation of apm-server.agent.config.cache.expiration on 32-bit architectures. (#15216)
• Change permissions of apm-server.yml in tar.gz artifacts to 0600. (#15627)