DKIM Message Body Hashes Broken with SFOS 17.5

Question

Since upgrading to SFOS 17.5, DKIM signed messages from internal mail servers no longer pass on DKIM body hash verification. 
 The DKIM signing is using 
 c=simple/relaxed; h=from:subject:to:date:message-id 
 which is the same signing method prior to the upgrade. 
 Current workaround is to add a rule above the auto-added rule for MTA mode, and make this rule allow the internal mail servers to talk directly to the recipient servers - bypassing the mail scanning rule that uses the MTA. 
 Anyone know why SFOS 17.5 is now breaking the message body, beyond basic whitespace formatting?

vishalpatel · Accepted Answer

Thanks for reporting the issue. We acknowledge the issue and we are tracking this defect with JIRA ID NC-43399.

Aditya Patel · Answer

Hello Mathias Mühlbacher , 
 The fix is scheduled in firmware version 17.5 MR6 ( NC-43399 ).