Starting with the 8.9.4 App Control server, valid signing certificates were required for all files contained in Windows App Control agent installation packages. In February 2023, the signing certificate used to validate SHA-1 MSI's in the 8.9.4 server expired, which will prevent any future Windows App Control agent installation packages from being properly validated and installed with this server version.
We recommend both customers who do and do not use Windows XP/2003 on the 8.9.4 server upgrade to the 8.9.6 server to ensure there are no issues with future release installations. The 8.9.6 Server contains an updated SHA-1 signing signature required to validate future installation packages of the Windows App Control agent.
Customers who do not wish to upgrade to the 8.9.6 server must manually apply the new SHA-1 signing certificate to prevent these issues from occurring. This new signing certificate is available for download below.