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What's new with Azure Connected Machine agent

Warning

Effective January 2026, the Azure Connected Machine agent will no longer accept certificates with negative serial numbers, in compliance with RFC 5280 Section 4.1.2.2, which states that "the serial number MUST be a positive integer assigned by the CA to each certificate."

The Azure Connected Machine agent receives improvements on an ongoing basis. To stay up to date with the most recent developments, this article provides you with information about:

  • The latest releases
  • Known issues
  • Bug fixes

This page is updated monthly, so revisit it regularly. If you're looking for items older than six months, you can find them in archive for What's new with Azure Connected Machine agent.

Important

Starting from version 1.56 of the Connected Machine agent for Windows (excluding Windows Server 2012 and Windows Server 2012 R2), you must configure cipher suites for at least one of the recommended TLS versions. For more information, see Windows TLS configuration issues.

Warning

Only Connected Machine agent versions released within the last year are officially supported by the product group. All customers should update to an agent version within this window or enable automatic agent upgrades (preview). Microsoft recommends staying up to date with the latest agent version whenever possible.

Version 1.59 - December 2025

Download for Windows or Linux

Feature Windows Linux Change Type
Guest Config 1.26.102.0 1.29.102.0
Increased unzipped extension package size limit from 400 MB to 1GB Improvement
Changed behavior on extension install when extension files already exist. Now, install will continue after attempting cleanup instead of failing. Improvement
Updated bundled PowerShell version from 7.4.7 to 7.4.13. Improvement
Updated Azure Storage API version from 2019-02-02 to 2025-11-05. Improvement
Azcmagent 1.59 1.59
Improved error handling for regional identity service network check. Bug Fix
Added new authentication method for azcmagent to use Azure CLI credentials for azcmagent connect and disconnect. Improvement
Fixed crashes caused by concurrent access of the agent's local config. Bug Fix
Updated Configuration UI to talk to Azure Resource Graph API to allow access on subscriptions with inherited permissions. Improvement

Version 1.58 - November 2025

Download for Windows or Linux

Feature Windows Linux Change Type
Guest Config 1.29.101.0 1.26.101.0
Updated OpenSSL library to version 3.6.0 (Windows) and 3.4.3 (Linux) for enhanced security and performance. Improvement
Use "systemctl daemon-reload" instead of "systemctl daemon-reexec" for better stability and compatibility. Improvement
Added customization support for Linux CIS Baseline and ASB security policies. Improvement
Azcmagent 1.58.03224.2567 1.58.03224.693
Enhanced log security by escaping newline characters to prevent log injection attacks. Bug Fix
Removed Preview flag from connection.type configuration property as the Arc gateway feature has been promoted to General Availability. Bug Fix
Fixed metadata synchronization: machine FQDN. Bug Fix
Fixed Windows installer service configuration issues when launched via double-click instead of elevated execution. Bug Fix
Fixed security validation to recognize Built-in Administrator account during named pipe ownership verification. Bug Fix

Version 1.57 - October 2025

Download for Windows or Linux

Feature Windows Linux Change Type
Guest Config 1.29.100.0
Fixed GC worker crashes on Windows Server 2012 Standard machines. Bug Fix
Azcmagent 1.57.03197.2516 1.57.03197.640
Connectivity check now marks regional GAS endpoint required Feature
Fixed duplicate heartbeat requests that were causing HTTP 429 (Too Many Requests) responses from HIS. Bug Fix
Fixed MSI installer incorrectly removing Arc services during installation. Bug Fix
Fixed RPM installer to install GC and EXT services before starting HIMDS. Bug Fix

Known Issues

If the Windows installer is launched by double-clicking (followed by the UAC prompt), it may fail to configure the Arc services properly. To ensure successful installation, please use one of the following methods:

  • Right-click the installer and select Run as administrator, or

  • Execute the installer using msiexec from an elevated PowerShell or Command Prompt.

Version 1.56 - September 2025

Download for Windows or Linux

Feature Windows Linux Change Type
Guest Config 1.29.99.0 1.26.94.0
Increased timeout when retrieving data from HIMDS on Azure Local servers. Bug Fix
Azcmagent 1.56.03167.2465 1.56.03167.593
Added support for ARM64 Debian 12. New Distro Support
Declared bundled OpenSSL in the spec file on RPM-based OSes. Security, Bug Fix
Azcmagent commands requiring admin privileges now confirm the pipe owner as HIMDS during IPC. Security, Bug Fix
Enforces minimum-required TLS cipher-suite enablement. Security, Bug Fix
Removed requests concerning the Arc gateway feature for ALDO (Azure Local Disconnected Operations). Bug Fix
Increased token acquisition timeout. Bug Fix
HIMDS now reports 'service stop' only after cleanup tasks complete. Bug Fix

Version 1.55 - August 2025

Download for Windows or Linux

Fixed

  • Improved logic to accurately detect whether the server is Azure Local.

  • Arc proxy no longer requests tokens from HIMDS unless explicitly enabled.

  • [Windows Only] Minor accessibility improvements to the GUI application.

Version 1.54 - July 2025

Download for Windows or Linux

Fixed

  • Fixed issues related to double-free memory errors and updating policy compliance status.

  • [Linux Only] Updated Boost on Linux to resolve service start issues caused by compatibility problems.

  • [Linux Only] Corrected Arc proxy log file permission during upgrade.

  • [Windows Only] Updated local PATH environment variable to resolve service install/delete errors.

New features and enhancements

  • Added support for managed identity-based custom policy downloads.

Note

This article contains updates covering the past six months. For earlier releases, see Archive for What's new with Azure Connected Machine agent

Next steps

  • Before evaluating or enabling Azure Arc-enabled servers across multiple hybrid machines, read Connected Machine agent overview to understand requirements, technical details about the agent, and deployment methods.
  • Review the Planning and deployment guide to plan for deploying Azure Arc-enabled servers at any scale and implement centralized management and monitoring.