If you install Veeam 9.5 update 4a and then try to upgrade the components on a remote Windows Server 2008 R2 server and this fails, the following can help to resolve the issue
Disable driver signature enforcement (https://en.miui.com/thread-237673-1-1.html)
Install Microsoft KB3033929 to enable SHA-2 on the server (https://support.microsoft.com/en-us/help/3033929/microsoft-security-advisory-availability-of-sha-2-code-signing-support)