Countercept Agent for Windows – 2026-04-01 – Ultralight Core update

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