Joel,
DisplayLink drivers are signed. We don't/cannot put unsigned drivers on Windows Update and 7.9 M4 is the same package as used in Windows Update for Windows 10.
Our drivers used to be signed TWICE. By us, then by Microsoft.
Microsoft advised us to stop signing because their signature was enough. So we did.
By updating, you will get Microsoft way of checking digital signatures (certificates most likely) which they probably changed since you last got a cumulative security patch.
If we sign, then we hit another Microsoft bug on Windows 10 which forces computers which don't have the zero day package (or later security patch) into recovery mode because the way of checking the signatures has an issue with dates.
Error message: Windows requires a digitally signed driver