Oops. I have misinformed you. I apologize! I had a closer look, and this is what I have found:
The property does exist - if you have typed it in, it would compile. But it is well hidden from IntelliSense etc. - because it does not, actually, work. Here is my comment to in the (also hidden) part of the documentation:
DO NOT SET THIS PROPERTY. Currently, any non-null value different from the global settings will cause an
error upon connection to the endpoint, because endpoint-specific certificate acceptance policy cannot be
reliably implemented with the underlying UA stack.</para>
So conceptually, it belongs there, but I cannot make it work well with the current underlying .NET stack from OPC Foundation. This is (roughly said) because the certificate validation is done on a callback from the stack which cannot be associated with the request that has triggered it. I suspect that when the CertificateAcceptancePolicy was in InstanceParameters in 5.35, it did not work reliably either.
So, instead of good news, I have bad news. But, one reason (besides my poor memory) I responded incorrectly was because I have confused this property with EndpointSelectionPolicy, which is exposed and visible on the UAEndpointDescriptor and can be set freely, and this is what users typically need to set. Looking at the contents of the CertificateAcceptancePolicy, there isn't much in there that would typically need to be set differently on different connections. What is the use case and background of this request? Which part of the CertificateAcceptancePolicy do they need to set separately? Or is it simply because they have programmed their system in hope that it would work, so now - understandably - this is felt as unwanted regression?
Kind regards
