Releases

v0.155.0 is a breaking-change release for operators: seven stabilized feature gates are removed, memory_limiter metrics get a new prefix, and two config/service APIs are deprecated in favor of snapshot-based replacements. The rest is tooling work on mdatagen and the newly relocated schemagen CLI.

• breakingSeven stabilized feature gates removed

  Applies to any collector build referencing confighttp.framedSnappy, configoptional.AddEnabledField, confmap.newExpandedValueSanitizer, exporter.PersistRequestContext, otelcol.printInitialConfig, telemetry.UseLocalHostAsDefaultMetricsAddress, or pdata.enableRefCounting via --feature-gates flags or config. These gates are gone in v0.155.0; startup will fail if they're still referenced. Drop them from your CLI args and config before upgrading.

• breakingmemory_limiter metrics renamed with processor prefix

  Applies to anyone scraping or alerting on otelcol_processor_* metrics from the memory_limiter processor. They're renamed to otelcol_processor_memory_limiter_* to disambiguate from other processors. Update dashboards, alert rules, and metric queries to the new names.

• breakingmdatagen reaggregation_enabled setting removed

  Applies to custom components using mdatagen metadata.yaml with reaggregation_enabled. The setting is removed; per-metric reaggregation config is now always generated. Old files with the field are still accepted but the value is ignored, so check generated output matches expectations.

• breakingConfig watcher APIs deprecated for snapshot-based equivalents

  Applies to extension or core code using service.Settings.CollectorConf or extensioncapabilities.ConfigWatcher. Both are deprecated in favor of service.Settings.ConfigSnapshot and extensioncapabilities.ConfigSnapshotWatcher. No forced migration yet, but plan to move to the snapshot-based APIs.

OTel Collector v0.154.0 fixes a startup crash in exporterhelper and changes --skip-get-modules behavior. Two minor enhancements add TLS and CORS config options.

• securityinclude_insecure_cipher_suites is opt-in — keep it that way

  The new configtls option lets you re-enable weak cipher suites, but they stay disabled by default. Do not set include_insecure_cipher_suites: true in production unless you're forced to by a legacy peer — and if you are, treat it as a temporary workaround and track it.

• breakingCheck custom build pipelines using --skip-get-modules

  If your OCB-based build scripts pass --skip-get-modules expecting go.mod to be regenerated as a side effect, that no longer happens. Audit any CI pipelines that relied on this implicit behavior and add an explicit go mod tidy step if needed.

• enhancementUpgrade if you use sending_queue with sizer enabled

  The nil-pointer panic fix in exporterhelper is critical for anyone who sets sending_queue.sizer alongside batch.enabled: false. If your collector was crashing on startup in this config, v0.154.0 resolves it — upgrade directly.

v0.153.0 stabilizes seven feature gates (breaking), fixes a critical memory corruption bug in gRPC Snappy compression, and ships several mdatagen enhancements for component authors.

• securityUpgrade immediately if you use gRPC with Snappy compression

  The Snappy fix in configgrpc addresses memory corruption that can cause fatal errors — this is a process-crash-level issue, not just a performance concern. If your exporters or receivers use gRPC with Snappy compression enabled, treat this as a priority upgrade. Check your exporter configs for compression: snappy settings.

• breakingAudit your feature gate overrides before upgrading

  All seven stabilized gates are now permanent behavior — you can no longer toggle them. If your collector config or startup flags reference configoptional.AddEnabledField, confmap.newExpandedValueSanitizer, exporter.PersistRequestContext, otelcol.printInitialConfig, pdata.useCustomProtoEncoding, telemetry.UseLocalHostAsDefaultMetricsAddress, or pdata.enableRefCounting, remove those references or the collector will fail to start. The metrics address change (UseLocalHostAsDefaultMetricsAddress) is the one most likely to surprise teams — your metrics endpoint is now localhost-bound by default.

• breakingmdatagen reaggregation config is now on by default

  If you maintain custom collector components using mdatagen, the reaggregation config fields are now generated by default. To preserve the old behavior (metrics config with only the enabled field), explicitly set reaggregation_enabled: false in your metadata.yaml. Run mdatagen on your components after upgrading and review the generated output before committing.

v0.152.1 is a bug-fix-heavy release with one useful new metric. The most operationally impactful changes are snappy decompression security fixes and a Prometheus metric naming regression fix.

• securityconfighttp snappy fixes limit memory exposure from compressed payloads

  Three snappy decompression fixes land in `pkg/confighttp`: body is now closed after reading, panics in decompression libraries return HTTP 400 instead of crashing with 500, and `max_request_body_size` is enforced before the decoded buffer is allocated. The size-check fix in particular prevents a potential memory spike from a maliciously crafted compressed payload. If you accept compressed OTLP over HTTP from untrusted sources, upgrade.

• breakingPrometheus metric name format may change if you customized telemetry host

  If you explicitly set the `host` field in the telemetry metrics section of your collector config, check whether your Prometheus metric names changed after upgrading to recent versions. The bug caused `WithoutScopeInfo`, `WithoutUnits`, and `WithoutTypeSuffix` to default to false instead of true in that code path, which means your metrics may have had unexpected suffixes or scope labels. This release restores the correct defaults — metric names may shift again on upgrade, so update dashboards and alerts accordingly.

• enhancementAdd in-flight exporter metric to your dashboards

  The new `otelcol_exporter_in_flight_requests` UpDownCounter metric is available in `pkg/exporterhelper`. Add it to your dashboards to see when exporters are queuing up requests or saturating worker pools — it's a direct signal of export backpressure that was previously hard to observe without custom instrumentation.

v0.152.0 fixes a silent Prometheus metric name regression when telemetry host is customized, changes AsString HTML-escaping behavior for map/slice values, and adds an in-flight exporter requests metric.

• breakingCheck Prometheus metric names if you customized telemetry host

  The Prometheus exporter boolean fields (WithoutScopeInfo, WithoutUnits, WithoutTypeSuffix) now default correctly when you explicitly set the telemetry host. Before this fix, those fields defaulted to false instead of true, so your metric names would silently change format. If you run a Collector with a custom telemetry host configured, verify your Prometheus metric names after upgrading — dashboards and alerts keyed on metric name format may need updating.

• breakingAsString output change for map/slice values — check downstream consumers

  pcommon.Value.AsString no longer HTML-escapes <, >, and & in map and slice values. If your pipeline or downstream consumers were relying on escaped output (e.g., &lt; or &gt;) from attribute maps or slices, the raw characters will now appear instead. Audit any log parsers, attribute processors, or exporters that inspect string representations of map/slice values.

• enhancementAdd otelcol_exporter_in_flight_requests to exporter dashboards

  A new UpDownCounter metric otelcol_exporter_in_flight_requests tracks concurrent export requests per exporter. Add it to your Collector dashboards to detect exporter worker pool saturation before it causes backpressure or dropped data. No config change needed — it emits automatically.

v0.151.0 has one API-level breaking change in the OTLP receiver config struct and changes the default behavior of the builder's go.mod generation. Dual-stack gRPC connection fixes and a pprofile data corruption fix are the most operationally relevant improvements.

• breakingUpdate OTLP receiver config field access in custom collectors

  The OTLP receiver's Config.Protocols is now a named field — any code accessing cfg.GRPC or cfg.HTTP directly will fail to compile. Update those references to cfg.Protocols.GRPC and cfg.Protocols.HTTP before upgrading collector builds that embed or extend the OTLP receiver.

• breakingCheck generated collector go.mod if you commit builder output

  cmd/builder now writes relative paths in Go module replace statements by default. For teams that build the collector, commit the generated source, and run it on multiple machines, this is an improvement. If you have tooling that depends on absolute paths (e.g., scripts parsing go.mod), set dist::use_absolute_replace_paths: true to preserve the old behavior while you migrate.

• enhancementFix dual-stack DNS connection issues with passthrough gRPC resolver

  Teams running OTLP gRPC exporters in dual-stack DNS environments have reported connection issues since the grpc.NewClient migration. You can now work around this by setting the endpoint to passthrough:///host:port in your exporter config. If you've seen intermittent connection failures in IPv4/IPv6 mixed environments, try this first.