All methods of filtering journal mailboxes support Microsoft Exchange Server Envelope Journaling. This feature ensures that target addresses in all BCC, Undisclosed and Alternate Recipient fields are captured.

If you have journal filtering enabled and intend enabling Envelope Journaling, we recommend that you test your existing filters and check the results before enabling Envelope Journaling on your production Exchange Server. Filters that only identify sender and recipient addresses, but do not attempt to modify the message, should continue to work as before. Addresses will be identified, even if they are classed as undisclosed recipients. Filters that attempt to modify the message will fail, as the envelope message (with the original message attached) is passed to the filters, instead of just the original message.

Before enabling Envelope Journaling, you will need to make changes to any proprietary journal filters that modify the selected message, so that the envelope message or the original message are accessed, as required. See "Custom filtering" in the Application Programmer's Guide for more information.