The update is related to the Countercept Agent’s Sensor component. The Sensor component gathers data to be analyzed in the WithSecure backend to identify any malicious activity. 

Product Name: Countercept Agent for Windows – Sensor Component

Version: 2026.2.37

Pilot Availability: 11/05/2026

General Availability: 25/05/2026

Predecessor: 2026.1.40

Release Purpose:

• New Features and Enhancements
• Generic maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
   for more details.

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• fsatp.sys
• fsatpl.exe
• fsatpn.exe
• install.exe
• sensor_control.exe

New Features and Enhancements:

• New detections and monitoring improvements

General Maintenance:

• Bug fixes and dependency updates

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Ultralight Core. Ultralight Core provides low-level functionality such as file hash calculation as part of the agent’s reporting of endpoint activity.

Product Name: Countercept Agent for Windows – Ultralight Core

Version: 2.1.21833

Pilot Availability: 20/04/2026

General Availability: 23/04/2026

Predecessor: 2.1.21758

Release Purpose:

• General maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
     for more details.
  Any endpoints which are not ACS-compliant will continue to run the older version of the Ultralight Core (2.1.16183).

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• CapricornScanner.exe
• install.exe
• uninstall.exe

New Features and Enhancements:

• N/A

General Maintenance:

• General maintenance of functionality not utilized by Countercept.

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the response component of the Countercept Agent, which enables the Detection and Response Team to retrieve artefacts for analysis or contain any identified threats within the environment.

Product Name: Countercept Agent for Windows – Response component

Version:

• 1.0.530.395

Pilot Availability: 09/04/2026

General Availability: 20/04/2026

Predecessor:

• 1.0.333.332 

Release Purpose:

• New features and enhancements 

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• install.exe

New Features and Enhancements:

• Added ARM64 support 

General Maintenance:

• Updates to third-party libraries and vulnerability fixes

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Response Engine (RE) and Common Response Actions Module (CRAM) components. The Response Engine and Common Response Actions Module components of the Countercept Agent enable the Detection and Response Team to retrieve artefacts for analysis or contain any identified threats within the environment. 

Product Name: Countercept Agent for Windows – CRAM and RE

Version:

• Response Engine 3.3.3
• CRAM 3.30.35

Pilot Availability: 09/04/2026

General Availability: 21/04/2026

Predecessor:

• Response Engine 3.3.2
• CRAM 3.8.19

Release Purpose:

• New features and enhancements 

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• ffind.exe
• fls.exe
• fscram-response.exe
• icat.exe
• ifind.exe
• mmcat.exe
• mmls.exe
• mmstat.exe
• verify.exe
• winpmem_1.6.2.exe
• winpmem_2.1.post4.exe
• winpmem_mini_x64_rc2.exe

New Features and Enhancements:

• Added ARM64 support

General Maintenance:

• Updates to third-party libraries and vulnerability fixes

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

This is a notification that the update to our Windows agent’s Ultralight Core planned for GA release tomorrow, 2nd of April 2026, has been postponed until Thursday, 16th of April. The update went to Pilot group endpoints on the 26th of March 2026. Events received from the Pilot group identified the need to adjust sensor side rules before going to General Availability.

The update is related to the Countercept Agent’s Ultralight Core. Ultralight Core provides low-level functionality such as file hash calculation as part of the agent’s reporting of endpoint activity.

Product Name: Countercept Agent for Windows – Ultralight Core

Version: 2.1.21739

Pilot Availability: 26/03/2026

General Availability: 16/04/2026

Predecessor: 2.1.21258

Release Purpose:

• General maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
    for more details.
  Any endpoints which are not ACS-compliant will continue to run the older version of the Ultralight Core (2.1.16183).

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• CapricornScanner.exe
• fshoster64.exe
• FsPisces.exe
• install.exe
• jsondump64.exe
• uninstall.exe

New Features and Enhancements:

• N/A

General Maintenance:

• General maintenance of functionality not utilized by Countercept.

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Sensor component. The Sensor component gathers data to be analyzed in the WithSecure backend to identify any malicious activity. 

Product Name: Countercept Agent for Windows – Sensor Component

Version: 2026.1.40

Pilot Availability: 03/03/2026

General Availability: 17/03/2026

Predecessor: 2025.3.64

Release Purpose:

• New Features and Enhancements
• Generic maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
        for more details.

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• fsatp.sys
• fsatpl.exe
• fsatpn.exe
• install.exe
• sensor_control.exe

New Features and Enhancements:

• New detections and monitoring improvements
• Additional tampering protection

General Maintenance:

• Bug fixes and dependency updates

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Security Cloud Core component. The Security Cloud Core component provides means for accessing WithSecure’s Security Cloud functionalities utilized by the agent’s detection components.

Product Name: Countercept Agent for Windows – Security Cloud Core

Version: 2.1.21205

Pilot Availability: 09/02/2026

General Availability: 16/02/2026

Predecessor: 2.1.20961

Release Purpose:

• General maintenance

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• install.exe

New Features and Enhancements:

• N/A

General Maintenance:

• General maintenance of functionality not utilized by Countercept.

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Ultralight Core. Ultralight Core provides low-level functionality such as file hash calculation as part of the agent’s reporting of endpoint activity.

Product Name: Countercept Agent for Windows – Ultralight Core

Version: 2.1.21258

Pilot Availability: 09/02/2026

General Availability: 17/02/2026

Predecessor: 2.1.21134

Release Purpose:

• General maintenance

Customer Action Required:

• The Operating System should be Azure Code Signing (ACS) compliant to receive this update. See 
  
  https://community.withsecure.com/en/kb/articles/29714-changes-in-support-on-microsoft-windows-minimum-patch-level
  
  
   for more details.
  Any endpoints which are not ACS-compliant will continue to run the older version of the Ultralight Core (2.1.16183).

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• CapricornScanner.exe
• fshoster64.exe
• install.exe
• jsondump64.exe
• uninstall.exe

New Features and Enhancements:

• N/A

General Maintenance:

• General maintenance of functionality not utilized by Countercept.

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Response Engine (RE) and Common Response Actions Module (CRAM) components. The Response Engine and Common Response Actions Module components of the Countercept Agent enable the Detection and Response Team to retrieve artefacts for analysis or contain any identified threats within the environment. 

Product Name: Countercept Agent for Windows – CRAM and RE

Version:

• Response Engine 3.3.2
• CRAM 3.8.19

Pilot Availability: 26/01/2026

General Availability: 02/02/2026

Predecessor:

• Response Engine 3.1.33
• CRAM 3.8.19

Release Purpose:

• General maintenance

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• ffind.exe
• fls.exe
• fscram-response.exe
• icat.exe
• ifind.exe
• mmcat.exe
• mmls.exe
• mmstat.exe
• verify.exe
• winpmem_1.6.2.exe
• winpmem_2.1.post4.exe
• winpmem_mini_x64_rc2.exe

New Features and Enhancements:

• N/A

General Maintenance:

• Updates to third-party libraries and vulnerability fixes

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025

The update is related to the Countercept Agent’s Ultralight Updater. Ultralight Core provides low-level functionality such as file hash calculation as part of the agent’s reporting of endpoint activity.

Product Name: Countercept Agent for Windows – Ultralight Updater

Version: 2.1.20910

Pilot Availability: 15/01/2026

General Availability: 22/01/2026

Predecessor: 2.1.19173

Release Purpose:

• General maintenance

Customer Action Required:

• N/A

Name Changes:

• No changes to file, process, or service names.

Files Updated:

• install.exe 
• ulu.exe 
• ulu_handler.exe 
• ulu_handler_ns.exe 

New Features and Enhancements:

• N/A

General Maintenance:

• General maintenance of functionality not utilized by Countercept.

OS Support:

• Windows 10, 11
• Windows Server 2012, 2012 R2, 2016, 2019, 2022, 2025