Change8

Azure Functions

Backend & Infra

The host/runtime that powers Azure Functions

Latest: v4.1047.10061 releases2 breaking changes21 common errorsView on GitHub

Release History

v4.1047.1002 fixes2 features
Jan 30, 2026

This release focuses on enhancing observability by adding OTEL environment variable support and improving health check diagnostics, alongside updating underlying language worker versions.

v4.1046.1001 fix4 features
Dec 16, 2025

This release introduces a new "web app" configuration profile and enhances health checks by adding the AzureWebJobsStorage check and ErrorCode telemetry. A bug affecting webPubSubTrigger on Flex consumption SKUs has also been resolved.

v4.846.1001 feature
Dec 10, 2025

This release updates several Azure WebJobs and AppService dependencies and enables worker indexing for Logic Apps under specific environment settings.

v4.1044.3501 fix
Nov 6, 2025

This release primarily focuses on an internal improvement by adding an empty remote message check within the SystemLogger.

v4.1045.2001 fix
Nov 6, 2025

This release primarily focuses on an internal improvement by adding an empty remote message check within the SystemLogger.

v4.1044.5001 fix
Nov 6, 2025

This release introduces a minor improvement to the SystemLogger by adding a check for empty remote messages.

v4.845.1001 feature
Oct 30, 2025

This release updates several Azure WebJobs and Functions related dependencies and enables worker indexing for Logic Apps under specific environment settings.

v4.1045.1004 fixes5 features
Oct 28, 2025

This release introduces configuration resolution from probing paths, enables worker indexing for Logic Apps, and includes several fixes related to health check metrics and sync trigger payloads. A diagnostic warning is now emitted for deprecated Azure Functions Proxies usage.

v4.1044.4003 fixes2 features
Oct 20, 2025

This release updates middleware dependencies, refines sync trigger payloads by removing duplicates, and improves health check metric reporting. It also introduces custom port configuration for Functions host in Custom Handler scenarios.

v4.1044.300
Oct 1, 2025

This release updates the Python Worker Version to 4.40.2.

v4.844.1001 fix
Sep 30, 2025

This release updates the Microsoft.Azure.WebJobs reference and adjusts default extension bundle version capping for v4.x on .NET 6, while ensuring limits are ignored in placeholder mode.

v4.644.1001 fix
Sep 30, 2025

This release updates dependency references, including Microsoft.Azure.WebJobs to 3.0.42, and adjusts default version capping for v4.x extension bundles on .NET 6.

v4.1044.2001 feature
Sep 26, 2025

This release updates the Python Worker Version to 4.40.1 and introduces JitTrace Files for version v4.1044.

v4.1044.100Breaking2 fixes5 features
Sep 26, 2025

This release focuses on improving telemetry handling, adding health checks, introducing configuration profiles, and updating various language worker versions. A significant change is the removal of the request size limit between the Host and Worker.

v4.643.3001 feature
Sep 16, 2025

This release introduces a change to ignore bundle version limits when the host is operating in placeholder mode.

v4.641.3001 fix
Sep 11, 2025

This release addresses an issue where bundle version limits were incorrectly applied when the host was in placeholder mode.

v4.641.200
Sep 5, 2025

The release caps the default version range for Cap v4.x extension bundles when targeting .NET 6 to be greater than 4.2.0 and less than 4.22.0.

v4.643.200
Sep 5, 2025

The release caps the default version range for Cap v4.x extension bundles when targeting .NET 6 to be greater than 4.2.0 and less than 4.22.0.

v4.1043.200
Sep 3, 2025

This release updates the Python Worker version to 4.39.2 and includes significant refactoring of the telemetry and exporter setup, introducing API updates and deprecations.

v4.843.1001 feature
Sep 3, 2025

This release allows sync triggers in managed environments without AzureWebJobsStorage set and updates the underlying Azure Functions host middleware dependency.

v4.643.1001 feature
Sep 3, 2025

This release allows sync triggers in managed environments without AzureWebJobsStorage set and updates the underlying Azure Functions Host middleware dependency.

v4.1043.1001 fix3 features
Sep 3, 2025

This release focuses on adding JitTrace files, updating dependencies like OTel packages and the Node.js Worker version, and includes a fix for a custom handler streaming bug.

v4.1042.1004 fixes2 features
Aug 1, 2025

This release introduces new activity sources for Durable and WebJobs (Kafka/RabbitMQ) and resolves a startup deadlock issue. It also adds a warning for older, unsupported bundle versions.

v4.842.1001 fix
Jul 24, 2025

This release adjusts the logging severity level within the DiagnosticEventTableStorageRepository to use Warning instead of Error for certain reported issues.

v4.1041.2001 fix
Jul 10, 2025

This release primarily addresses an issue related to loading the extensions configuration file.

v4.1041.1002 fixes2 features
Jun 24, 2025

This release focuses heavily on performance improvements, including numerous memory allocation optimizations across various components and enhanced coldstart pipeline capabilities. It also introduces support for cross-platform perf tracing and fixes an invocation timeout issue.

v4.841.1001 feature
Jun 19, 2025

This release updates the Java and Python worker versions and adds specific configuration support for Logic Apps PowerShell apps.

v4.641.1001 fix1 feature
Jun 19, 2025

This release updates the Java and Python worker versions and introduces support for a new environment variable for configuring PowerShell workers in Logic Apps.

v4.1040.3001 fix
Jun 17, 2025

This release introduces case-insensitive serialization.

v4.1040.2002 fixes
May 28, 2025

This release includes a fix for the Instance Manager related to CV1 Migration and prevents OTel/AzMon exporter setup in placeholder mode. The Java Worker version has also been updated.

v4.1039.6001 fix
May 27, 2025

This release primarily focuses on fixing an issue within the Instance Manager concerning CV1 Migration.

v4.1040.1003 fixes6 features
May 19, 2025

This release focuses on improving memory metrics reporting on Linux via CGroup data and includes several internal optimizations and bug fixes, notably addressing a GrpcWorkerChannel concurrency issue.

v4.840.1003 fixes1 feature
May 15, 2025

This release introduces an option to exclude test data from the /functions endpoint and resolves several bugs related to circular dependencies and concurrency issues in gRPC workers. It also updates underlying worker versions.

v4.640.1003 fixes1 feature
May 15, 2025

This release introduces an option to exclude test data from the /functions endpoint and resolves several bugs related to circular dependencies and concurrency issues in gRPC workers. It also includes updates to underlying worker versions.

v4.839.5001 fix
May 9, 2025

This release addresses an issue by disabling Diagnostic Events when Table Storage is inaccessible.

v4.639.5001 fix
May 9, 2025

This minor release addresses an issue by disabling Diagnostic Events when Table Storage is inaccessible.

v4.1039.5001 fix
May 2, 2025

This release addresses an issue by disabling Diagnostic Events when Table Storage is unavailable.

v4.839.400
Apr 16, 2025

This release updates the PowerShell 7.4 worker to version 4.0.4206.

v4.639.400
Apr 16, 2025

This release updates the PowerShell worker version to 4.0.4206.

v4.1039.4001 fix1 feature
Apr 16, 2025

This release updates the PowerShell 7.4 worker version and adjusts runtime handling for Linux builds.

v4.839.3001 fix1 feature
Apr 16, 2025

This release improves memory metrics reporting on Linux by utilizing CGroup data and resolves a circular dependency issue in the Linux container metrics publisher.

v4.639.3001 fix1 feature
Apr 16, 2025

This release focuses on improving memory metrics reporting on Linux systems by utilizing CGroup data and resolving a circular dependency issue.

v4.1039.3001 fix1 feature
Apr 16, 2025

This release focuses on infrastructure improvements, specifically enhancing memory metrics reporting on Linux via CGroup data and resolving a circular dependency issue.

v4.839.2001 feature
Apr 11, 2025

This release introduces JitTrace Files for version 4.39.

v4.639.2001 feature
Apr 11, 2025

This release primarily introduces JitTrace Files for version 4.39.

v4.1039.2001 feature
Apr 11, 2025

This release introduces JitTrace Files specifically for version v4.1039.

v4.839.1003 fixes2 features
Apr 9, 2025

This release includes updates to the Java, PowerShell, and Python workers, introduces a new feature flag for Azure Monitor time formatting, and resolves several bugs related to TimerTriggers, race conditions on Linux, and extension bundle resolution.

v4.639.1003 fixes2 features
Apr 9, 2025

This release updates the Java, PowerShell, and Python worker versions and introduces new features for Azure Monitor logging format and platform release channel configuration, alongside several bug fixes.

v4.1039.1006 fixes6 features
Apr 9, 2025

This release introduces support for response compression and various bug fixes related to DateTime handling, race conditions during warmup, and binding uniqueness. It also updates Python and Java worker versions.

v3.25.01 fix
Apr 2, 2025

This release marks the end-of-life for v3.x runtimes and includes an update to the domain used for the CDN URI.

v4.1038.4001 feature
Mar 19, 2025

This release updates the PowerShell worker import process by explicitly keeping the 'unix' runtime for Linux builds.

v4.1038.3002 fixes
Mar 14, 2025

This release updates the Java Worker to version 2.18.1 and the PowerShell worker to 4.0.4206, alongside a bug fix for platform release channel casing issues.

v4.1038.2002 fixes
Mar 14, 2025

This release focuses on fixing bugs related to DateTime handling, specifically addressing issues with TimeZones in TimerTriggers and invalid DateTimes in status blobs.

v4.1038.100Breaking8 fixes5 features
Mar 14, 2025

This release focuses on enhancing observability through improved log forwarding and managed identity support, alongside several bug fixes related to binding parsing and worker stability. A key change is the migration of WebJobs.Script to target .NET 8.

v4.638.2001 fix1 feature
Mar 14, 2025

This release introduces support for the `WEBSITE_PlatformReleaseChannel` setting for extension bundle resolution and fixes a casing issue related to this resolution.

v4.838.2001 fix1 feature
Mar 14, 2025

This release introduces support for the `WEBSITE_PlatformReleaseChannel` setting for extension bundles resolution and includes a bug fix related to casing issues in bundle resolution.

v4.838.1002 fixes
Mar 14, 2025

This release focuses on updating various language workers (Java, PowerShell, Python) and improving HTTP proxy error handling for client disconnects. It also updates underlying .NET dependency versions.

v4.638.1002 fixes
Mar 14, 2025

This release focuses on updating various language workers (Java, Python, PowerShell) and improving internal HTTP proxy error handling for client disconnects. It also updates dependency versions for .NET 6 and 8.

v4.1037.11 fix
Feb 21, 2025

This minor release focuses on fixing a specific exception related to timers.

v4.637.11 fix
Feb 20, 2025

This minor release focuses on fixing an ArgumentOutOfRangeException related to timers.

v4.837.11 fix
Feb 20, 2025

This minor release focuses on fixing an ArgumentOutOfRangeException related to timers.

Common Errors

ObjectDisposedException5 reports

ObjectDisposedException in Azure Functions often arises from accessing services or objects after the function host has been recycled or shut down. Resolve this by ensuring all service scopes are properly managed and disposed of within the function's execution context. Avoid storing dependencies obtained from IServiceProvider as static or long-lived objects, and leverage dependency injection scopes ("using" statements or IDisposable pattern) to guarantee resource disposal after use.

FunctionInvocationException4 reports

FunctionInvocationException in Azure Functions commonly arises from unhandled exceptions within your function code or incompatibilities between the host and function dependencies. Ensure robust error handling with try-catch blocks in your function, and verify that your function app's dependencies are compatible with the Azure Functions runtime version you're using. Review the function execution logs in Azure Monitor for detailed stack traces to pinpoint the root cause and address it directly within your function code or deployment configuration.

InternalServerError4 reports

"InternalServerError" in Azure Functions often indicates a problem within the Azure infrastructure or the function app's configuration, preventing successful execution. To fix it: Review your function app's configuration, ensuring key vault references, managed identities, and dependencies are correctly configured and accessible. If the issue persists, check the Azure status page for any service outages and consider restarting the function app or redeploying to force a refresh of the environment.

HttpRequestException3 reports

HttpRequestException in Azure Functions commonly arises from network connectivity issues, DNS resolution failures, or problems reaching the intended endpoint. To resolve this, ensure your function app has proper outbound network access (e.g., configure outbound IPs or VNet integration), verify DNS settings, and confirm that the target service is reachable and responsive. Check firewall rules on both the function app and the target service, and consider using Application Insights to diagnose network-related errors.

HandleWorkerInitError2 reports

HandleWorkerInitError often arises from issues within the worker process initialization, such as missing dependencies, incorrect configurations, or errors in the worker's startup script/code. To resolve it, thoroughly review the worker's configuration, ensure all required dependencies are installed correctly (especially those specified in requirements.txt for Python), and carefully examine the worker's initialization logs/code for any exceptions or errors preventing successful startup. Restarting the function app or worker instance can sometimes resolve transient dependency issues.

InvalidOperationException2 reports

InvalidOperationException in Azure Functions often stems from concurrent access or modification of shared resources, especially during startup or shutdown processes. To fix this, implement proper locking mechanisms (e.g., using `AsyncLock` or `SemaphoreSlim`) to serialize access to critical shared resources or collections. Ensure that background tasks or threads using shared resources gracefully terminate before the host shuts down to prevent race conditions and incomplete operations.

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