Kernel extensions signed before Apr 7, 2019 are unable to load on macOS 10.14.5

Hi,


I have macOS 10.14.5 (18F132) installed and having three different builds of my product as below :


Case 1. Kernel extensions signed on macOS 10.9.5 in Oct 2018 (with —timestamp=none)

These extensions were loaded successfully on macOS 10.14.5.

Case 2. Kernel extensions signed on macOS 10.9.5 in Feb 2019 (with —timestamp=none)

These extensions were unable to load on macOS 10.14.5.

Case 3. Kernel extensions signed on macOS 10.13.6 in June 2019 (with —timestamp)

These extensions are notarized using Apple notary service and loads successfully on macOS 10.14.5


My query is :

As per macOS 14.5 release notes : Kernel extension signed after Apr 7, 2019 has to be notarized in order to load on macOS 10.14.5 but in above mentioned case#2 extension signed in Feb 2019 is unable to load.


If we consider this due to missing timestamp, then how come in case#1 kernel extension is loaded successfully?

Somewhere our observations do not match the release notes of macOS 10.14.5, but we are unable to understand the reason behind it.