Traces

• Define sampling threshold field in OpenTelemetry TraceState; define the behavior
  of TraceIdRatioBased sampler in terms of W3C Trace Context Level 2 randomness.
  (#4166)
• Define CompositeSampler implementation and built-in ComposableSampler interfaces.
  (#4466)
• Define how SDK implements Tracer.Enabled.
  (#4537)

Logs

• Stabilize Event Name parameter of Logger.Enabled.
  (#4534)
• Stabilize SDK and No-Op Logger.Enabled.
  (#4536)
• SeverityNumber=0 MAY be used to represent an unspecified value.
  (#4535)

Compatibility

• Clarify expectations about Prometheus content negotiation for metric names.
  (#4543)

Supplementary Guidelines

• Add Supplementary Guidelines for environment variables as context carrier
  specification.
  (#4548)

OTEPs

• Extend attributes to support complex values.
  (#4485)

Common

• Update spec to comply with OTEP-232.
  (#4529)

New Contributors

• @ArthurSens made their first contribution in #4543

Metrics

• Prometheus receiver can expect otel_scope_schema_url and otel_scope_[attribute] labels on all metrics.
  (#4505)
• Prometheus receiver no longer expects otel_scope_info metric.
  (#4505)
• Prometheus exporter adds otel_scope_schema_url and otel_scope_[attribute] labels on all metrics.
  (#4505)
• Prometheus exporter no longer exports otel_scope_info metric.
  (#4505)

Entities

• Define rules for setting identifying attributes.
  (#4498)
• Define rules for entity-resource referencing model.
  (#4499)

Common

• Move Instrumentation Scope definition from glossary to a dedicated document and use normative language.
  (#4488)

Context

• Drop reference to binary Propagator.
  (#4490)

Logs

• Add optional Event Name parameter to Logger.Enabled and LogRecordProcessor.Enabled.
  (#4489)

Resource

• Add experimental resource detector name.
  (#4461)

OTEPs

• OTEP: Span Event API deprecation plan.
  (#4430)

v1.44.0 (2025-04-15)

Context

• Add context propagation through Environment Variables specification.
  (#4454)
• On Propagators API, stabilize GetAll on the TextMap Extract.
  (#4472)

Traces

• Define sampling threshold field in OpenTelemetry TraceState; define the behavior
  of TraceIdRatioBased sampler in terms of W3C Trace Context Level 2 randomness.
  (#4166)

Metrics

• Clarify SDK behavior for Instrument Advisory Parameter.
  (#4389)

Logs

• Add Enabled opt-in operation to the LogRecordProcessor.
  (#4439)
• Stabilize Logger.Enabled.
  (#4463)
• Stabilize EventName.
  (#4475)

Baggage

• Add context (baggage) propagation through Environment Variables specification.
  (#4454)

Resource

• Add Datamodel for Entities.
  (#4442)

SDK Configuration

• Convert declarative config env var substitution syntax to ABNF.
  (#4448)
• List declarative config supported SDK extension plugin interfaces.
  (#4452)

New Contributors

• @Nevay made their first contribution in #4456
• @adrielp made their first contribution in #4454

Full Changelog: v1.43.0...v1.44.0

v1.43.0 (2025-03-18)

Traces

• Clarify STDOUT exporter format is unspecified.
  (#4418)

Metrics

• Clarify the metrics design goal, scope out StatsD client support.
  (#4445)
• Clarify STDOUT exporter format is unspecified.
  (#4418)

Logs

• Clarify that it is allowed to directly use Logs API.
  (#4438)
• Clarify STDOUT exporter format is unspecified.
  (#4418)

Supplementary Guidelines

• Add Advanced Processing to Logs Supplementary Guidelines.
  (#4407)

OTEPs

• Composite Head Samplers.
  (#4321)

v1.42.0 (2025-02-18)

Traces

• Deprecate exception.escaped attribute, add link to in-development semantic-conventions on how to record errors across signals.
  (#4368)
• Define randomness value requirements for W3C Trace Context Level 2.
  (#4162)

Logs

• Define how SDK implements Logger.Enabled.
  (#4381)
• Logs API should have functionality for reusing Standard Attributes.
  (#4373)

SDK Configuration

• Define syntax for escaping declarative configuration environment variable references.
  (#4375)
• Resolve various declarative config TODOs.
  (#4394)

v1.41.0 (2025-01-21)

Logs

• Remove the deprecated Events API and SDK in favor of having Events support in the Logs API and SDK.
  (#4353)
• Remove Logger's Log Instrumentation operations.
  (#4352)
• Make all Logger operations user-facing.
  (#4352)

SDK Configuration

• Clarify that implementations should interpret timeout environment variable
  values of zero as no limit (infinity).
  (#4331)

v1.40.0 (2024-12-12)

Context

• Adds optional GetAll method to Getter in Propagation API, allowing for the retrieval of multiple values for the same key.
  #4295

Traces

• Add in-development support for otlp/stdout exporter via OTEL_TRACES_EXPORTER.
  (#4183)
• Remove the recommendation to not synchronize access to TracerConfig.disabled.
  (#4310)

Metrics

• Add in-development support for otlp/stdout exporter via OTEL_METRICS_EXPORTER.
  (#4183)
• Remove the recommendation to not synchronize access to MeterConfig.disabled.
  (#4310)

Logs

• Add in-development support for otlp/stdout exporter via OTEL_LOGS_EXPORTER.
  (#4183)
• Remove the recommendation to not synchronize access to LoggerConfig.disabled.
  (#4310)
• Remove the in-development isolating log record processor.
  (#4301)

Events

• Deprecate Events API and SDK in favor of having Events support in the Logs API and SDK.
  (#4319)
• Change event.name attribute into top-level event name field.
  (#4320)

Common

• Lay out core principles for Specification changes.
  (#4286)

Supplementary Guidelines

• Add core principles for evaluating specification changes.
  (#4286)

OTEPs

• The open-telemetry/oteps repository was merged into the specification repository.
  (#4288)

New Contributors

• @CharlieTLe made their first contribution in #4289
• @jamesmoessis made their first contribution in #4295

v1.39.0 (2024-11-07)

Logs

• Simplify the name "Logs Instrumentation API" to just "Logs API".
  (#4258)
• Rename Log Bridge API to Logs API. Define the existing Logger methods to be
  Log Bridge Operations. Add EmitEvent to the Logger as an Instrumentation Operation.
  (#4259)

Profiles

• Define required attributes for Mappings.
  (#4197)

Compatibility

• Add requirement to allow extending Stable APIs.
  (#4270)

SDK Configuration

• Clarify declarative configuration parse requirements for null vs empty.
  (#4269)

Common

• Define prototype for proposed features in development.
  (#4273)

New Contributors

• @florianl made their first contribution in #4197

v1.38.0 (2024-10-10)

Traces

• Make all fields as identifying for Tracer. Previously attributes were omitted from being identifying.
  (#4161)
• Clarify that Export MUST NOT be called by simple and batching processors concurrently.
  (#4205)

Metrics

• Make all fields as identifying for Meter. Previously attributes were omitted from being identifying.
  (#4161)
• Add support for filtering attribute keys for streams via an exclude list.
  (#4188)
• Clarify that Enabled only applies to synchronous instruments.
  (#4211)
• Clarify that applying cardinality limits should be done after attribute filtering.
  (#4228)
• Mark cardinality limits as stable.
  (#4222)

Logs

• Make all fields as identifying for Logger. Previously attributes were omitted from being identifying.
  (#4161)
• Define Enabled parameters for Logger.
  (#4203)
  (#4221)
• Introduce initial placeholder for the new user-facing Logs API, adding references
  to existing API's informing of the coming changes while the definition is defined.
  (#4236)

Common

• Define equality for attributes and collection of attributes.
  (#4161)
• Update Instrumentation Scope glossary entry with correct identifying fields
  (#4244)

New Contributors

• @yuanyuanzhao3 made their first contribution in #4216
• @MSNev made their first contribution in #4236