Deprecated

April 23, 2026 · View on GitHub

This document lists all the items currently deprecated in opentelemetry-cpp.

Deprecated items will be removed in the future.

[Build scripts]

CMake WITH_OTLP_RETRY_PREVIEW

Announcement (WITH_OTLP_RETRY_PREVIEW)

The CMake compile flag WITH_OTLP_RETRY_PREVIEW is deprecated by:

Enable WITH_OTLP_RETRY_PREVIEW by default #3953

Motivation (WITH_OTLP_RETRY_PREVIEW)

Flags like WITH_OTLP_RETRY_PREVIEW are used to conditionally compile new features, when they are introduced in the code base.

Now that this feature is stable, conditional compilation is no longer necessary.

Scope (WITH_OTLP_RETRY_PREVIEW)

Remove compilation flag WITH_OTLP_RETRY_PREVIEW in CMake.

Remove ifdef ENABLE_OTLP_RETRY_PREVIEW in C++ .

Mitigation (WITH_OTLP_RETRY_PREVIEW)

Applications built with WITH_OTLP_RETRY_PREVIEW=ON need to:

remove the WITH_OTLP_RETRY_PREVIEW flag from CMake scripts

Applications built with WITH_OTLP_RETRY_PREVIEW=OFF need to:

remove the WITH_OTLP_RETRY_PREVIEW flag from CMake scripts
use retry_policy_max_attempts = 0 in the OTLP exporter options.

For Bazel, no compilation option exists, the bazel build enables unconditionally ENABLE_OTLP_RETRY_PREVIEW.

Make sure to properly initialize retry_policy_max_attempts to enable or disable the retry feature.

Planned removal (WITH_OTLP_RETRY_PREVIEW)

This compilation flag will be removed after October 1st, 2026.

CMake WITH_OTLP_GRPC_SSL_MTLS_PREVIEW

Announcement (WITH_OTLP_GRPC_SSL_MTLS_PREVIEW)

The CMake compile flag WITH_OTLP_GRPC_SSL_MTLS_PREVIEW is deprecated by:

Enable WITH_OTLP_GRPC_SSL_MTLS_PREVIEW by default #3970

Motivation (WITH_OTLP_GRPC_SSL_MTLS_PREVIEW)

Flags like WITH_OTLP_GRPC_SSL_MTLS_PREVIEW are used to conditionally compile new features, when they are introduced in the code base.

Now that this feature is stable, conditional compilation is no longer necessary.

Scope (WITH_OTLP_GRPC_SSL_MTLS_PREVIEW)

Remove compilation flag WITH_OTLP_GRPC_SSL_MTLS_PREVIEW in CMake.

Remove ifdef ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW in C++ .

Mitigation (WITH_OTLP_GRPC_SSL_MTLS_PREVIEW)

Applications built with WITH_OTLP_GRPC_SSL_MTLS_PREVIEW=ON need to:

remove the WITH_OTLP_GRPC_SSL_MTLS_PREVIEW flag from CMake scripts

Applications built with WITH_OTLP_GRPC_SSL_MTLS_PREVIEW=OFF need to:

remove the WITH_OTLP_GRPC_SSL_MTLS_PREVIEW flag from CMake scripts
initialize ssl client properties in the OTLP GRPC exporter options, either with real KEY and CERT data, or with empty strings.

See:

struct OtlpGrpcClientOptions
struct OtlpGrpcLogRecordExporterOptions
struct OtlpGrpcMetricExporterOptions
struct OtlpGrpcExporterOptions

For Bazel, no compilation flag exists, the code is always built using ENABLE_OTLP_GRPC_SSL_MTLS_PREVIEW.

Make sure to properly initialize ssl client properties to enable or disable the feature.

Planned removal (WITH_OTLP_GRPC_SSL_MTLS_PREVIEW)

This compilation flag will be removed after October 1st, 2026.

[opentelemetry-cpp API]

Deprecation of EventLogger

Announcement (EventLogger)

The EventLogger API was deprecated by:

[API] Deprecate event logger #3285

on Feb 25, 2025, as published in release 1.20.

Motivation (EventLogger)

The specification for EventLogger was deprecated by:

Deprecate Event API and SDK in favor of Emit Event in the Log API #4319

The opentelemetry-cpp API and SDK deprecates the EventLogger to be aligned with the opentelemetry specification.

Scope (EventLogger)

The following classes or methods are deprecated in ABI version 1:

API
- class opentelemetry::logs::EventLogger
- class opentelemetry::logs::EventLoggerProvider
- class opentelemetry::logs::NoopEventLogger
- class opentelemetry::logs::NoopEventLoggerProvider
- method opentelemetry::logs::Provider::GetEventLoggerProvider()
- method opentelemetry::logs::Provider::SetEventLoggerProvider()
SDK
- class opentelemetry::sdk::logs::EventLogger
- class opentelemetry::sdk::logs::EventLoggerProvider
- class opentelemetry::sdk::logs::EventLoggerProviderFactory

The same are removed from ABI version 2.

Mitigation (EventLogger)

In respective order, the following should be used in place of EventLogger:

API
- class opentelemetry::logs::Logger
- class opentelemetry::logs::LoggerProvider
- class opentelemetry::logs::NoopLogger
- class opentelemetry::logs::NoopLoggerProvider
- method opentelemetry::logs::Provider::GetLoggerProvider()
- method opentelemetry::logs::Provider::SetLoggerProvider()
SDK
- class opentelemetry::sdk::logs::Logger
- class opentelemetry::sdk::logs::LoggerProvider
- class opentelemetry::sdk::logs::LoggerProviderFactory

Instrumented applications, that currently use opentelemetry::logs::Provider::GetEventLoggerProvider(), are strongly encouraged to migrate and use opentelemetry::logs::Provider::GetLoggerProvider() instead.

Main applications, when installing and configuring an SDK, that currently use opentelemetry::logs::Provider::SetEventLoggerProvider(), are strongly encouraged to migrate and use opentelemetry::logs::Provider::SetLoggerProvider() instead.

This migration can be implemented now, as Logger is available already in ABI version 1.

This migration is mandatory and a pre requisite for adoption of ABI version 2 later.

Planned removal (EventLogger)

All the deprecated code is already removed from ABI version 2, since Feb 2025.

While EventLogger will not be removed from ABI version 1, the ABI version 1 itself will be deprecated and decommissioned in the long term, after ABI version 2 is declared stable.

By the time only ABI version 2 is available and supported, any code still using the deprecated EventLogger will break.

Deprecation of plugin

Announcement (plugin)

The plugin API was deprecated by:

[API] Deprecate plugin #4021

on Apr 21, 2026.

Motivation (plugin)

All the code in namespace opentelemetry::plugin is a framework designed to help loading code from shared libraries.

This framework was never used.

Keeping the code in the repository has a maintenance cost (include-what-you-use, cpp-check, clang-tidy, CI), and also increases confusion.

This unused code is to be removed.

Scope (plugin)

The following files are to be removed from the API:

opentelemetry/plugin/*.h
opentelemetry/plugin/detail/*.h

The following files are to be removed from examples:

examples/plugin/*