• Remove calculation of sampling-score based on Context.User.Id Issue #625
• New sdk-driven "heartbeat" functionality added which sends health status at pre-configured intervals. See extending heartbeat properties doc for more information
• Fixes a bug in ServerTelemetryChannel which caused application to crash on non-windows platforms.
  [Details on fix and workaround #654] (#654)
  Original issue (microsoft/ApplicationInsights-aspnetcore#551)
• Fixed a bug with the AdaptiveSamplingTelemetryProcessor that would cause starvation over time. Issue #756 (dotnet-server)
• Updated solution to build on Mac!

• Method Sanitize on classes implementing ITelemetry no longer modifies the TelemetryContext fields. Serialized event json and ETW event will still have context tags sanitized.
• Application Insights SDK supports multiple telemetry sinks. You can configure more than one channel for telemetry now.
• New method DeepClone on ITelemetry interface. Implemented by all supported telemetry items.
• Server telemetry channel NuGet support a netstandard1.3 target with fixed rate sampling and adaptive sampling telemetry processors.
• Instrumentation key is no longer required for TelemetryClient to send data to channel(s). This makes it easier to use the SDK with channels other than native Application Insights channels.
• .NET 4.0 targets were removed. Please use the version 2.4.0 if you cannot upgrade your application to the latest framework version.
• Removed wp8, portable-win81+wpa81 and uap10.0 targets.

Includes all changes since 2.3.0 stable release.
Updated reference to System.Diagnostics.DiagnosticSource version 4.4.0

This release contains the following changes:

• Made Metric class private and fixed various metrics related issues.

You should also include an explicit reference to System.Diagnostics.DiagnosticSource 4.4.0-preview2-25330-01 since it contains a critical bug fix this release relies on (you can remove this reference when 2.4.0 stable ships with an updated reference).

• No product changes since beta2. Named changed to beta3 for consistent naming with ApplicationInsights Web SDK

• Removed metric aggregation functionality as there is not enough feedback on the API surface yet.

• Event telemetry is set to be sampled separately from all other telemetry types. It potentially can double the bill. The reason for this change is that Events are mostly used for usage analysis and should not be subject to sampling on high load of requests and dependencies. Edit ApplicationInsights.config file to revert to the previous behavior.
• Added dependency on System.Diagnostics.DiagnosticsSource package. It is still possible to use standalone Microsoft.ApplicationInsights.dll to track telemetry.
• StartOperation starts a new System.Diagnostics.Activity and stores operation context in it. StartOperation overwrites OperationTelemetry.Id set before or during telemetry initialization for the dependency correlation purposes.
• OperationCorrelationTelemetryInitializer initializes telemetry from the Activity.Current. Please refer to https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.DiagnosticSource/src/ActivityUserGuide.md for more details about Activity and how to use it
• Request.Success field will not be populated based on ResponseCode. It needs to be set explicitly.
• New "ProblemId" property on ExceptionTelemetry. It can be used to set a custom ProblemId value.
• Metric Aggregation functionality (originally added in 2.3.0-beta1 but removed in 2.3.0) is re-introduced.
• Improved exception stack trace data collection for .NET Core applications.

Includes all changes since 2.2.0 stable release.
Removed metric aggregation functionality added in 2.3.0-beta1 release.
Fixed a bug which caused SDK to stop sending telemetry.

Added overloads of TelemetryClientExtensions.StartOperation.
Fire new ETW events for Operation Start/Stop.