Thank you for your response. Good to learn that Spamsieve is compatible with Postbox 5.
What i was referring to was a rather confusing explanation that I received when searching that question with Google. Notice how many different versions and store purchase options are thrown into the mix as to which version works and which does not. It’s a bit overwhelming to figure out.
SpamSieve requires Postbox 2.0 or later. It is not compatible with Postbox Express. The Mac App Store version of Postbox does not support plug-ins, so it cannot work with SpamSieve. However, if you purchased Postbox from the Mac App Store you can download the full version of Postbox and use that with SpamSieve.
SpamSieve Manual: Setting Up Postbox - C-Command SpamSieve Manual: Setting Up Postbox
If Postbox already thinks that a message is junk, it may not let you mark it as junk—and likewise for not junk. That’s OK; it is enough to train SpamSieve by marking the messages that are misclassified in Postbox.