Most of the effort in the software business goes into the maintenance of code that already exists.

I want to avoid locking people into solutions that work only with Postfix. People should have a choice in what software they want to use with Postfix, be it anti-virus or otherwise.

For many people my software is something that you install and forget. I like to keep it that way.

My reply is: the software has no known bugs, therefore it has not been updated.

Writing software that's safe even in the presence of bugs makes the challenge even more interesting.

Postfix keeps running even if one Postfix process dies; Windows requires that someone restarts the service.

However, writing software without defects is not sufficient. In my experience, it is at least as difficult to write software that is safe - that is, software that behaves reasonably under adverse conditions.