Hmm… It doesn’t work. I commented out the “stop” and ran:
sievec sieve-spam.sieve # Recompile the sieve filter
chown mail:dovecot sieve-spam.svbin # Change owner back to original after recompiling
service dovecot restart # Restart dovecot just in case this is needed to pick up the newly modified filter (I’m not sure).
I tested this by sending spam test messages to myself with the string “XJSC4JDBQADN1.NSBN32IDNENGTUBE-STANDARD-ANTI-UBE-TEST-EMAILC.34X” in the body, which is designed specifically to test spam filters. The messages still went to spam despite a Roundcube filter to move them into the Inbox.
I’m not sure why it didn’t work.