Countercept Agent for Windows – 2026-05-29 – Ultralight Core update

Update to previous release schedule and version

Windows agent’s Ultralight Core release planned for General Available release on Monday, 8th of June 2026, has been cancelled due to an issue found during the Pilot phase. We apologize for the delays related to this particular release, but we are committed to making sure that we release content with the highest possible quality. 

A new version of Ultralight Core (2.1.22029) that fixes the issue found will be delivered to Pilot group endpoints on Monday, the 8th of June 2026, with a General Availability (GA) release on Monday, the 15th of June 2026.

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: 2.1.21987 / 2.1.22029

Pilot Availability: 01/06/2026 / 08/06/2026

General Availability: 08/06/2026 / 15/06/2026

Predecessor: 2.1.21833

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:

• fshoster64.exe
• FsPisces.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