The following changes are from the previous release 1.20.1.

• NuGet: OpenTelemetry v1.21.0-rc.1

  • Fixed a race in the self-diagnostics sink dispatcher where disposing it
    while its pump thread was exiting could throw ArgumentNullException on
    .NET Framework.
    (#7983)

  • SelfDiagnosticsOptions is now automatically bound from the
    OpenTelemetry:SelfDiagnostics configuration section, when present.
    (#8008)

  • Fixed a race where collecting a metric with delta temporality concurrently
    with the creation of a new MetricPoint could reclaim the MetricPoint
    while it was being created, losing the measurement.
    (#8019)

  • Fixed a race where collecting a metric with delta temporality could export
    the same series twice in a single collection.
    (#8019)

  • Fixed wildcard matching timeouts that could prevent configured source, meter,
    legacy activity, or metric view patterns from matching.
    (#8014)

  • The timeout passed to MetricReader.Collect() (for example by
    MeterProvider.ForceFlush()), the ExportTimeoutMilliseconds of
    PeriodicExportingMetricReader and the ExporterTimeoutMilliseconds of
    BatchExportProcessor<T> are now made available to the exporter instead of
    being ignored once the export has started, so that the OTLP exporter can
    cancel an export which runs past the timeout. The ExportTimeoutMilliseconds
    of PeriodicExportingMetricReader now also limits exports which are not
    started by the reader itself, such as those of MeterProvider.ForceFlush().
    (#7996)

  • Fixed a race where collecting a cumulative metric concurrently with the
    creation of a new MetricPoint could export a MetricPoint that was not yet
    fully initialized, could case a NullReferenceException when enumerating Tags.
    (#8018)

  • Breaking Change Dropped support for net8.0 and net9.0.
    (#6899)

  • Add support for .NET 11.0.
    (#6899)

  • Added support for enabling ActivitySources from configuration using the
    Microsoft.Extensions.Diagnostics tracing APIs introduced in .NET 11 (for
    example, services.AddTracing(b => b.AddConfiguration(section))).
    Activities from sources enabled this way are processed by the OpenTelemetry
    TracerProvider registered through AddOpenTelemetry().WithTracing().
    Not supported when targeting net10.0.
    (#6899)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.21.0-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.21.0-rc.1

  • Breaking Change Dropped support for net8.0 and net9.0.
    (#6899)

  • Add support for .NET 11.0.
    (#6899)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.21.0-rc.1

  • Fixed byte[]-valued tags being serialized as a JSON array of numbers
    (e.g. [1,2,3]) instead of being Base64-encoded as per the specification.
    (#7694)

  • Fixed array-valued tags containing NaN or infinite floating-point values
    being exported as TRUNCATED; such values are now written as JSON strings
    (e.g. ["NaN"]). Arrays and maps nested inside array-valued tags are now
    written as nested JSON (with byte[] values Base64-encoded) instead of as
    their .NET type name (e.g. System.Int32[]).
    (#7694)

  • Fixed arrays of string-valued key/value pairs being
    serialized as JSON arrays of strings instead of JSON objects.
    (#7694)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.21.0-rc.1

  • Breaking Change Dropped support for net8.0 and net9.0.
    (#6899)

  • Add support for .NET 11.0.
    (#6899)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.21.0-rc.1

  • Fixed experimental in-memory retries exceeding the export timeout when a
    retried request stalls.
    (#7977)

  • Breaking: The span status description (Activity.StatusDescription or
    the otel.status_description tag) is now truncated to the configured span
    attribute value length limit (for example
    OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT) instead of being exported in full.
    (#7995)

  • Redacted nonstandard OTLP endpoint paths in internal diagnostic logs with
    [REDACTED], while retaining standard HTTP and gRPC service paths.
    (#8016)

  • Fixed exports continuing until OtlpExporterOptions.TimeoutMilliseconds
    elapsed when a shorter timeout applied to them, such as the timeout passed
    to MeterProvider.ForceFlush(),
    PeriodicExportingMetricReaderOptions.ExportTimeoutMilliseconds
    (OTEL_METRIC_EXPORT_TIMEOUT) or
    BatchExportProcessorOptions<T>.ExporterTimeoutMilliseconds
    (OTEL_BSP_EXPORT_TIMEOUT, OTEL_BLRP_EXPORT_TIMEOUT). The request is now
    canceled when the shorter of the timeouts elapses. The time taken to
    serialize the telemetry now counts towards the timeout, and no request is
    sent once it has elapsed.
    (#7996)

  • Fixed arrays of string-valued key/value pairs being
    exported as arrays of strings instead of maps.
    (#7694)

  • Breaking Change Dropped support for net8.0 and net9.0.
    (#6899)

  • Add support for .NET 11.0.
    (#6899)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Zipkin v1.21.0-rc.1

  • Fixed array-valued tags containing NaN or infinite floating-point values
    being exported as TRUNCATED; such values are now written as JSON strings
    (e.g. ["NaN"]). Arrays and maps nested inside array-valued tags are now
    written as nested JSON (with byte[] values Base64-encoded) instead of as
    their .NET type name (e.g. System.Int32[]).
    (#7694)

  • Fixed arrays of string-valued key/value pairs being
    serialized as JSON arrays of strings instead of JSON objects.
    (#7694)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Hosting v1.21.0-rc.1

  • The OpenTelemetry providers are now initialized in
    IHostedLifecycleService.StartingAsync instead of IHostedService.StartAsync
    so that telemetry emitted by other hosted services during StartingAsync is
    captured. ITelemetryHostInitializer.Initialize() is invoked only once per
    host start.
    (#7998)

  • Breaking Change Dropped support for net8.0 and net9.0.
    (#6899)...

For highlights and announcements pertaining to this release see: Release Notes > 1.20.1.

The following changes are from the previous release 1.20.0.

• NuGet: OpenTelemetry v1.20.1

  • Fixed a possible race condition on ARM64 when multiple threads record the
    first measurement with no tags, or the first overflow measurement, that could
    cause the measurement to be recorded incorrectly.
    (#7951)

  • Fixed self-diagnostics preamble redaction of quoted or encoded PEM material
    and prefixed JWTs.
    (#7955)

  • Fixed default HTTP client log filtering when registering the OTLP log exporter
    through OpenTelemetryLoggerOptions.
    (#7959)

  • Fixed legacy self-diagnostics logging terminating the process when the log
    file is truncated or the log volume runs out of space.
    (#7956)

  • Experimental (pre-release builds only): Fixed Logger.EmitLog ignoring
    instrumentation suppression, which could cause recursive exports or deadlocks.
    (#7961)

  • Fixed delta double counters losing subsequent measurements after a non-finite
    or large value and idle metric points with a NaN value failing to be reclaimed.
    (#7963)

  • Improve the assignment of values to exponential histogram buckets when the
    value is near a bucket boundary by using a pre-computed lookup table.
    (#7911)

  • Fixed LogRecords being returned to the shared pool while still queued for
    export when an exporter stops enumerating a single-item or array
    Batch<LogRecord> early which could cause a BatchLogRecordExportProcessor
    on the same provider to export missing or incorrect data.
    (#7965)

  • Fixed a SuppressInstrumentationScope.Enter() reference count never being
    released when the Activity it was entered for is not recorded, which caused
    all subsequent telemetry in that execution context to be suppressed.
    (#7966)

  • Self-diagnostics log files, whether configured through OTEL_DIAGNOSTICS.json
    or SelfDiagnosticsOptions, are now always created as new files.
    (#7968)

  • Self-diagnostics messages written to the sinks configured by
    SelfDiagnosticsOptions are now truncated to 16,384 characters so that the
    memory used by entries waiting to be written is bounded.
    (#7969)

  • The self-diagnostics file sink now creates its log directory and log files
    so that only the owner can access them (0700/0600) on Linux and macOS,
    instead of inheriting the process umask.
    (#7967)

  • Fixed pooled log records retaining completed log data until reused.
    (#7978)

  • Fixed slow metric recording when distinct wide tag values, such as long or
    Guid, share the same built-in hash code.
    (#7979)

  • Fixed ObservableCounter and ObservableUpDownCounter overflow points
    reporting only the last observation instead of the sum for each collection.
    (#7985)

  • Fixed replaced log attributes being exported together with their original
    values when buffering or updating LogRecord.State.
    (#7987)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.20.1

  • Fixed TracerProvider.GetTracer caching a new tracer for each call with equal
    array-valued scope tags.
    (#7960)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.20.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.20.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.20.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.20.1

  • Fixed informational HTTP client logs not being suppressed by default when the
    OTLP log exporter is registered using OpenTelemetryLoggerOptions.AddOtlpExporter.
    (#7959)

  • Breaking: HttpClient instances created by the exporter directly no
    longer follow HTTP redirects. A 3xx response is now treated as a failed
    export. See Configure HttpClient
    to prevent HttpClient created by IHttpClientFactory from following
    redirects.
    (#7958)

  • The value of OTEL_EXPORTER_OTLP_ENDPOINT, or of its signal-specific
    variants, is no longer written to the exporter's diagnostic log when it is
    not a valid URI.
    (#7971)

  • Hardened the experimental disk retry feature.

    • When running on .NET on non-Windows platforms, the retry directory and
      the blob files within it are now created accessible to the current user
      only, including when the directory is recreated after being deleted.
    • Directory size accounting no longer follows subdirectories, avoiding
      a symbolic-link/junction walk.
    • Expired lease-file cleanup now correctly locates the lease timestamp
      delimiter within the file name rather than the whole path.
    • Storage maintenance no longer deletes or renames files with a .blob,
      .tmp or .lock extension that the exporter did not create when the
      retry directory is shared with other files. Only files named the way the
      exporter names its blobs, and the temporary and lease files derived from
      them, are now removed or renamed, and only blobs named that way are now
      retried.
    • Timestamps in blob and lease file names are now always written using the
      Gregorian calendar. Previously, when the current culture used a different
      calendar, files were given timestamps that caused them never to be
      removed or released when the storage was maintained.
    • A stored request whose lease has expired is no longer deleted after it has
      been retried, as it may have since been leased again for another retry.
    • Stored blobs that are empty or that are larger than the maximum size of
      the storage are no longer read. When running on .NET, stored blobs that
      are symbolic links are also no longer read.
      (#7857)

  • Only the first 4 KiB of the body of an unsuccessful response is now read and
    written to the exporter's diagnostic log, instead of up to
    MaxResponseSizeBytes.
    (#7969)

  • Fixed reading the body of a failed export response for the exporter's
    diagnostic log not being bounded by the export timeout.
    (#7970)

  • Fixed the body of a failed export response never being written to the
    exporter's diagnostic log when running on .NET Framework.
    (#7970)

  • Fixed attributes whose value is converted with ToString() (for example
    enums, Uri or StringValues) being dropped as unsupported, and for metric
    data points omitted from every later export, when the export buffer had to
    be resized while the attribute was being written.
    (#7973)

  • Breaking: Fixed telemetry stored by the experimental disk retry feature
    for one exporter being resent by another exporter for the same signal to ...

The following changes are from the previous release 1.20.0-beta.1.

• NuGet: OpenTelemetry.Exporter.Prometheus.AspNetCore v1.20.1-beta.1

  • Fixed scrape responses being handed to the server in a single write, which
    made the server buffer a full copy of the response for each client that did
    not read it until the request completed or timed out. Responses are now
    written in bounded slices so the server's back-pressure applies.
    (#7957)

  • Fixed startup scrapes permanently omitting target_info and configured
    resource constant labels from subsequent scrape responses.
    (#7984)

  • Updated OpenTelemetry core component version(s) to 1.20.1.
    (#7990)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Prometheus.HttpListener v1.20.1-beta.1

  • Fixed scrape responses being handed to the server in a single write, which
    on Linux and macOS made the listener allocate and hold a full copy of the
    response for each client that did not read it until the request completed or
    timed out. Responses are now written in bounded slices.
    (#7957)

  • Fixed scrape requests that announce a request body holding a thread pool
    thread after their response had been sent on Linux and macOS for as long as
    the client kept trickling in the body. The connection is now closed after
    responding to a request with a body instead of being kept alive.
    (#7962)

  • Fixed startup scrapes permanently omitting target_info and configured
    resource constant labels from subsequent scrape responses.
    (#7984)

  • Updated OpenTelemetry core component version(s) to 1.20.1.
    (#7990)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Shims.OpenTracing v1.20.1-beta.1

  • Updated OpenTelemetry core component version(s) to 1.20.1.
    (#7990)

  See CHANGELOG for details.

The following changes are from the previous release 1.20.0.

• NuGet: OpenTelemetry v1.20.1-rc.1

  • Fixed a possible race condition on ARM64 when multiple threads record the
    first measurement with no tags, or the first overflow measurement, that could
    cause the measurement to be recorded incorrectly.
    (#7951)

  • Fixed self-diagnostics preamble redaction of quoted or encoded PEM material
    and prefixed JWTs.
    (#7955)

  • Fixed default HTTP client log filtering when registering the OTLP log exporter
    through OpenTelemetryLoggerOptions.
    (#7959)

  • Fixed legacy self-diagnostics logging terminating the process when the log
    file is truncated or the log volume runs out of space.
    (#7956)

  • Experimental (pre-release builds only): Fixed Logger.EmitLog ignoring
    instrumentation suppression, which could cause recursive exports or deadlocks.
    (#7961)

  • Fixed delta double counters losing subsequent measurements after a non-finite
    or large value and idle metric points with a NaN value failing to be reclaimed.
    (#7963)

  • Improve the assignment of values to exponential histogram buckets when the
    value is near a bucket boundary by using a pre-computed lookup table.
    (#7911)

  • Fixed LogRecords being returned to the shared pool while still queued for
    export when an exporter stops enumerating a single-item or array
    Batch<LogRecord> early which could cause a BatchLogRecordExportProcessor
    on the same provider to export missing or incorrect data.
    (#7965)

  • Fixed a SuppressInstrumentationScope.Enter() reference count never being
    released when the Activity it was entered for is not recorded, which caused
    all subsequent telemetry in that execution context to be suppressed.
    (#7966)

  • Self-diagnostics log files, whether configured through OTEL_DIAGNOSTICS.json
    or SelfDiagnosticsOptions, are now always created as new files.
    (#7968)

  • Self-diagnostics messages written to the sinks configured by
    SelfDiagnosticsOptions are now truncated to 16,384 characters so that the
    memory used by entries waiting to be written is bounded.
    (#7969)

  • The self-diagnostics file sink now creates its log directory and log files
    so that only the owner can access them (0700/0600) on Linux and macOS,
    instead of inheriting the process umask.
    (#7967)

  • Fixed pooled log records retaining completed log data until reused.
    (#7978)

  • Fixed slow metric recording when distinct wide tag values, such as long or
    Guid, share the same built-in hash code.
    (#7979)

  • Fixed ObservableCounter and ObservableUpDownCounter overflow points
    reporting only the last observation instead of the sum for each collection.
    (#7985)

  • Fixed replaced log attributes being exported together with their original
    values when buffering or updating LogRecord.State.
    (#7987)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.20.1-rc.1

  • Fixed TracerProvider.GetTracer caching a new tracer for each call with equal
    array-valued scope tags.
    (#7960)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.20.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.20.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.20.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.20.1-rc.1

  • Fixed informational HTTP client logs not being suppressed by default when the
    OTLP log exporter is registered using OpenTelemetryLoggerOptions.AddOtlpExporter.
    (#7959)

  • Breaking: HttpClient instances created by the exporter directly no
    longer follow HTTP redirects. A 3xx response is now treated as a failed
    export. See Configure HttpClient
    to prevent HttpClient created by IHttpClientFactory from following
    redirects.
    (#7958)

  • The value of OTEL_EXPORTER_OTLP_ENDPOINT, or of its signal-specific
    variants, is no longer written to the exporter's diagnostic log when it is
    not a valid URI.
    (#7971)

  • Hardened the experimental disk retry feature.

    • When running on .NET on non-Windows platforms, the retry directory and
      the blob files within it are now created accessible to the current user
      only, including when the directory is recreated after being deleted.
    • Directory size accounting no longer follows subdirectories, avoiding
      a symbolic-link/junction walk.
    • Expired lease-file cleanup now correctly locates the lease timestamp
      delimiter within the file name rather than the whole path.
    • Storage maintenance no longer deletes or renames files with a .blob,
      .tmp or .lock extension that the exporter did not create when the
      retry directory is shared with other files. Only files named the way the
      exporter names its blobs, and the temporary and lease files derived from
      them, are now removed or renamed, and only blobs named that way are now
      retried.
    • Timestamps in blob and lease file names are now always written using the
      Gregorian calendar. Previously, when the current culture used a different
      calendar, files were given timestamps that caused them never to be
      removed or released when the storage was maintained.
    • A stored request whose lease has expired is no longer deleted after it has
      been retried, as it may have since been leased again for another retry.
    • Stored blobs that are empty or that are larger than the maximum size of
      the storage are no longer read. When running on .NET, stored blobs that
      are symbolic links are also no longer read.
      (#7857)

  • Only the first 4 KiB of the body of an unsuccessful response is now read and
    written to the exporter's diagnostic log, instead of up to
    MaxResponseSizeBytes.
    (#7969)

  • Fixed reading the body of a failed export response for the exporter's
    diagnostic log not being bounded by the export timeout.
    (#7970)

  • Fixed the body of a failed export response never being written to the
    exporter's diagnostic log when running on .NET Framework.
    (#7970)

  • Fixed attributes whose value is converted with ToString() (for example
    enums, Uri or StringValues) being dropped as unsupported, and for metric
    data points omitted from every later export, when the export buffer had to
    be resized while the attribute was being written.
    (#7973)

  • Breaking: Fixed telemetry stored by the experimental disk retry feature
    for one exporter being resent by another exporter for the same signal to its
    own endpoint and with its own headers. Disk retry storage is now additionally
    separated by a subdirectory derived fr...

For highlights and announcements pertaining to this release see: Release Notes > 1.20.0.

The following changes are from the previous release 1.19.1.

• NuGet: OpenTelemetry v1.20.0

  • Fixed SuppressInstrumentationScope reference counts leaking between inherited asynchronous execution contexts.
    (#7803)

  • Self-diagnostic features are explicitly disabled on browser-based platforms (e.g. Blazor) and are now non-functional. Previously, attempting to enable self-diagnostics on such platforms would result in an exception at runtime.
    (#7799)

  • Added TracerProviderBuilder.ConfigureSampler which receives the resolved Sampler whether set programmatically, via OTEL_TRACES_SAMPLER, or by default, and returns a replacement. Intended for library authors who need to influence sampling without overriding a sampler the application has configured.
    (#7780)

  • Fixed ResourceBuilder.CreateDefault ignoring OTEL_RESOURCE_ATTRIBUTES and OTEL_SERVICE_NAME environment variables when the host IConfiguration does not contain those settings.
    (#7855)

  • Added improved self-diagnostics logging to improve the support experience. The new SelfDiagnosticsOptions class configures a rolling file sink and a console sink through the standard options pipeline. Sinks are off by default.
    (#7588)

  • Fixed a race that could incorrectly route a concurrent metric measurement to the overflow point when its tag set was published as the cardinality limit was reached.
    (#7804)

  • Added OpenTelemetryLoggerOptions.Version and OpenTelemetryLoggerOptions.SchemaUrl options to set an instrumentation library version and schema URL applied to logs emitted via the Microsoft.Extensions.Logging ILogger integration.
    (#7727)

  • Fixed LogRecord.CategoryName resetting the current Logger's Version to null when set to a new value.
    (#7727)

  • Bounded the internal cache of Logger scopes keyed by instrumentation to avoid unbounded growth.
    (#7727)

  • Fixed the MeterProvider and its IServiceProvider being kept alive after the host is disposed when using Microsoft.Extensions.Diagnostics versions prior to 9.0, which never dispose their MetricsSubscriptionManager (and its underlying MeterListener).
    (#7924)

  • Fixed a race condition between recording a measurement and collecting a histogram with delta temporality that could cause an empty data point (with a count of zero) to be exported in the next collection cycle.
    (#7923)

  • Improved metric collection performance after metric streams are removed by compacting metric storage during collection.
    (#7945)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.20.0

  • Added Logger.SchemaUrl and a LoggerProvider.GetLogger overload accepting a schema URL parameter using the new LoggerOptions type.
    (#7727)

  • Breaking change (pre-release only versions): LoggerProvider's protected TryCreateLogger(string? name, out Logger? logger) extensibility method has been replaced by TryCreateLogger(LoggerOptions options, out Logger? logger). Custom LoggerProvider subclasses that override the previous overload must update to override the new one; the old overload is no longer called.
    (#7727)

  • Optimize performance of BaggagePropagator.Inject on .NET Framework using lookup tables.
    (#7947)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.20.0

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.20.0

  • ConsoleLogRecordExporter now writes an Instrumentation scope (Logger) section (Name, Version, and Schema URL) for each exported LogRecord.
    (#7727)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.20.0

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.20.0

  • Avoid closure allocations when serializing cached metric metadata.
    (#7841)

  • Custom TLS certificate options (custom CA trust and mTLS) and the experimental disk retry feature are explicitly marked as not supported on browser-based platforms (e.g. Blazor).
    (#7799)

  • Suppressed informational HTTP client logs from OTLP exporters by default. See HttpClient logging for configuration overrides.
    (#7743)

  • Avoid logging malformed HTTP request headers in the exporter's diagnostic log.
    (#7858)

  • Avoid buffering the whole compressed request body in memory before sending it on .NET Framework when using HTTP/protobuf with gzip compression.
    (#7879)

  • The OTLP log exporter now exports schema_url on ScopeLogs. Log records emitted from a Logger with a schema URL set now populate ScopeLogs.schema_url in exported OTLP requests.
    (#7727)

  • Breaking: byte[] attributes longer than the configured attribute value length limit (for example OTEL_ATTRIBUTE_VALUE_LENGTH_LIMIT) are now truncated to that many bytes instead of being exported in full.
    (#7893)

  • Breaking: OTEL_EVENT_ATTRIBUTE_COUNT_LIMIT and OTEL_LINK_ATTRIBUTE_COUNT_LIMIT now fall back to OTEL_ATTRIBUTE_COUNT_LIMIT (then the default of 128) when not set, instead of falling back to OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT.
    (#7894)

  • Breaking: Instrumentation scope attributes exported from ActivitySource.Tags are now limited by OTEL_ATTRIBUTE_COUNT_LIMIT instead of OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT. Only applications that set OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT to a different value from OTEL_ATTRIBUTE_COUNT_LIMIT are affected.
    (#7902)

  • Fixed log records being dropped when using OtlpExportProtocol.HttpProtobuf with IHttpClientFactory integration if the first export of logs happens while the IServiceProvider is being disposed. The exporter now falls back to the default HttpClient instead of failing the export.
    (#7916)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Zipkin v1.20.0

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Hosting v1.20.0

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Propagators v1.20.0

  No notable changes.

...

The following changes are from the previous release 1.19.1-beta.1.

• NuGet: OpenTelemetry.Exporter.Prometheus.AspNetCore v1.20.0-beta.1

  • A scrape request whose connection is aborted, or whose X-Prometheus-Scrape-Timeout-Seconds deadline elapses, now stops waiting for an in-progress metrics collection instead of continuing to wait for it to finish. The collection itself is not cancelled and continues running in the background.
    (#7856)

  • Updated OpenTelemetry core component version(s) to 1.20.0.
    (#7950)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Prometheus.HttpListener v1.20.0-beta.1

  • Updated OpenTelemetry core component version(s) to 1.20.0.
    (#7950)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Shims.OpenTracing v1.20.0-beta.1

  • Updated OpenTelemetry core component version(s) to 1.20.0.
    (#7950)

  See CHANGELOG for details.

The following changes are from the previous release 1.19.1.

• NuGet: OpenTelemetry v1.20.0-rc.1

  • Fixed SuppressInstrumentationScope reference counts leaking between inherited asynchronous execution contexts.
    (#7803)

  • Self-diagnostic features are explicitly disabled on browser-based platforms (e.g. Blazor) and are now non-functional. Previously, attempting to enable self-diagnostics on such platforms would result in an exception at runtime.
    (#7799)

  • Added TracerProviderBuilder.ConfigureSampler which receives the resolved Sampler whether set programmatically, via OTEL_TRACES_SAMPLER, or by default, and returns a replacement. Intended for library authors who need to influence sampling without overriding a sampler the application has configured.
    (#7780)

  • Fixed ResourceBuilder.CreateDefault ignoring OTEL_RESOURCE_ATTRIBUTES and OTEL_SERVICE_NAME environment variables when the host IConfiguration does not contain those settings.
    (#7855)

  • Added improved self-diagnostics logging to improve the support experience. The new SelfDiagnosticsOptions class configures a rolling file sink and a console sink through the standard options pipeline. Sinks are off by default.
    (#7588)

  • Fixed a race that could incorrectly route a concurrent metric measurement to the overflow point when its tag set was published as the cardinality limit was reached.
    (#7804)

  • Added OpenTelemetryLoggerOptions.Version and OpenTelemetryLoggerOptions.SchemaUrl options to set an instrumentation library version and schema URL applied to logs emitted via the Microsoft.Extensions.Logging ILogger integration.
    (#7727)

  • Fixed LogRecord.CategoryName resetting the current Logger's Version to null when set to a new value.
    (#7727)

  • Bounded the internal cache of Logger scopes keyed by instrumentation to avoid unbounded growth.
    (#7727)

  • Fixed the MeterProvider and its IServiceProvider being kept alive after the host is disposed when using Microsoft.Extensions.Diagnostics versions prior to 9.0, which never dispose their MetricsSubscriptionManager (and its underlying MeterListener).
    (#7924)

  • Fixed a race condition between recording a measurement and collecting a histogram with delta temporality that could cause an empty data point (with a count of zero) to be exported in the next collection cycle.
    (#7923)

  • Improved metric collection performance after metric streams are removed by compacting metric storage during collection.
    (#7945)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.20.0-rc.1

  • Added Logger.SchemaUrl and a LoggerProvider.GetLogger overload accepting a schema URL parameter using the new LoggerOptions type.
    (#7727)

  • Breaking change (pre-release only versions): LoggerProvider's protected TryCreateLogger(string? name, out Logger? logger) extensibility method has been replaced by TryCreateLogger(LoggerOptions options, out Logger? logger). Custom LoggerProvider subclasses that override the previous overload must update to override the new one; the old overload is no longer called.
    (#7727)

  • Optimize performance of BaggagePropagator.Inject on .NET Framework using lookup tables.
    (#7947)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.20.0-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.20.0-rc.1

  • ConsoleLogRecordExporter now writes an Instrumentation scope (Logger) section (Name, Version, and Schema URL) for each exported LogRecord.
    (#7727)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.20.0-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.20.0-rc.1

  • Avoid closure allocations when serializing cached metric metadata.
    (#7841)

  • Custom TLS certificate options (custom CA trust and mTLS) and the experimental disk retry feature are explicitly marked as not supported on browser-based platforms (e.g. Blazor).
    (#7799)

  • Suppressed informational HTTP client logs from OTLP exporters by default. See HttpClient logging for configuration overrides.
    (#7743)

  • Avoid logging malformed HTTP request headers in the exporter's diagnostic log.
    (#7858)

  • Avoid buffering the whole compressed request body in memory before sending it on .NET Framework when using HTTP/protobuf with gzip compression.
    (#7879)

  • The OTLP log exporter now exports schema_url on ScopeLogs. Log records emitted from a Logger with a schema URL set now populate ScopeLogs.schema_url in exported OTLP requests.
    (#7727)

  • Breaking: byte[] attributes longer than the configured attribute value length limit (for example OTEL_ATTRIBUTE_VALUE_LENGTH_LIMIT) are now truncated to that many bytes instead of being exported in full.
    (#7893)

  • Breaking: OTEL_EVENT_ATTRIBUTE_COUNT_LIMIT and OTEL_LINK_ATTRIBUTE_COUNT_LIMIT now fall back to OTEL_ATTRIBUTE_COUNT_LIMIT (then the default of 128) when not set, instead of falling back to OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT.
    (#7894)

  • Breaking: Instrumentation scope attributes exported from ActivitySource.Tags are now limited by OTEL_ATTRIBUTE_COUNT_LIMIT instead of OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT. Only applications that set OTEL_SPAN_ATTRIBUTE_COUNT_LIMIT to a different value from OTEL_ATTRIBUTE_COUNT_LIMIT are affected.
    (#7902)

  • Fixed log records being dropped when using OtlpExportProtocol.HttpProtobuf with IHttpClientFactory integration if the first export of logs happens while the IServiceProvider is being disposed. The exporter now falls back to the default HttpClient instead of failing the export.
    (#7916)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Zipkin v1.20.0-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Hosting v1.20.0-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Propagators v1.20.0-rc.1

  No notable changes.

  See [CHANGELOG](https://github.com/open-telemetr...

For highlights and announcements pertaining to this release see: Release Notes > 1.19.1.

The following changes are from the previous release 1.19.0.

• NuGet: OpenTelemetry v1.19.1

  • Fixed NotSupportedException thrown when building a TracerProvider or MeterProvider with a large number of wildcard source/meter patterns on net8.0, and a related OutOfMemoryException that could occur when many such providers were built over the lifetime of a process.
    (#7788)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.19.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.19.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.19.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.19.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.19.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Zipkin v1.19.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Hosting v1.19.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Propagators v1.19.1

  No notable changes.

  See CHANGELOG for details.

The following changes are from the previous release 1.19.0-beta.1.

• NuGet: OpenTelemetry.Exporter.Prometheus.AspNetCore v1.19.1-beta.1

  • Updated OpenTelemetry core component version(s) to 1.19.1.
    (#7796)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Prometheus.HttpListener v1.19.1-beta.1

  • Updated OpenTelemetry core component version(s) to 1.19.1.
    (#7796)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Shims.OpenTracing v1.19.1-beta.1

  • Updated OpenTelemetry core component version(s) to 1.19.1.
    (#7796)

  See CHANGELOG for details.

The following changes are from the previous release 1.19.0.

• NuGet: OpenTelemetry v1.19.1-rc.1

  • Fixed NotSupportedException thrown when building a TracerProvider or MeterProvider with a large number of wildcard source/meter patterns on net8.0, and a related OutOfMemoryException that could occur when many such providers were built over the lifetime of a process.
    (#7788)

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Api.ProviderBuilderExtensions v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Console v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.InMemory v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.OpenTelemetryProtocol v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Exporter.Zipkin v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Hosting v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.

• NuGet: OpenTelemetry.Extensions.Propagators v1.19.1-rc.1

  No notable changes.

  See CHANGELOG for details.