Last night I upgraded to Build 9504 the usual way, turn off smartermail website in IIS, uninstalled the old built and installed the new one... and I had a moment of panic... all certificates stopped working. 

I use the certificate folder in smartermail.

I had to redefine the user for the certificates, reset the password and the path in IIS and regive permission to the certificate user to the folder in smartermail. No idea why it happened but it happened.

It was good however as I realized also that smartermail now wants bindings in IIS for http not only https. Meaning I was receiving a lot of messages for certificates that were not renewing because inaccessible through http, and I guess smarter mail uses http rather than https to validate the domain for the certificate (which it makes sense... when I installed my smartermail many years ago, lots of this was done manually so there was no need to have http in bindings for smartermail except for mail.domain.com to port 80).

However... adding bindings in IIS smartermail site like smtp.domain.com pop.domain.com imap.domain.com all for http port 80... solved all conflicts that were coming up with certificate renewals.

I wished they had it listed somewhere... I did had bindings for smtp, pop, imap but they were all for https port 443. Not having the bindings for hhtp port 80 was creating problems with automatic certificate renewal.

I hope it helps somebody else...