You appear to have mixed up your Micros
Micro Focus Knowledge Partner
The KB2921916 HotFix is for The "Untrusted publisher dialog box appears when you install a driver in Windows 7 or Windows Server 2008 R2" issue and is needed to do a silent install of the OES Client as discussed in several threads including this one: OES Client MDT Silent unattended install with no prompts.
As Julian_DC pointed out, it is no longer available for download from the Microsoft site. Instead, as a workaround, Microsoft suggests an upgrade to Windows 10. :-(
I don't know where to obtain the hotfix or if it can legally be redistributed. I do know there are a lot of Windows 7 systems out there and not having access to this hotfix could be a major issue for many customers.
Perhaps Alan Adams can suggest a workaround?