Limitations

OpenTelemetry tracesedit

Traces of applications using messaging semantics might be wrongly displayed as transactions in the Applications UI, while they should be considered spans (see issue #7001).
Inability to see Stack traces in spans.
Inability in APM views to view the "Time Spent by Span Type" (see issue #5747).

OpenTelemetry logsedit

[preview] This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features. The OpenTelemetry logs intake via Elastic is in technical preview.
The application logs data stream (app_logs) has dynamic mapping disabled. This means the automatic detection and mapping of new fields is disabled (see issue #9093).

OpenTelemetry Line Protocol (OTLP)edit

Elastic supports both the (OTLP/gRPC) and (OTLP/HTTP) protocol with ProtoBuf payload. Elastic does not yet support JSON Encoding for OTLP/HTTP.

OpenTelemetry Collector exporter for Elasticedit

The OpenTelemetry Collector exporter for Elastic has been deprecated and replaced by the native support of the OpenTelemetry Line Protocol in Elastic Observability (OTLP). To learn more, see migration.

The OpenTelemetry Collector exporter for Elastic (which is different from the legacy exporter mentioned above) is not intended to be used with Elastic APM and Elastic Observability Serverless. Use Elastic’s native OTLP support instead.