@Bob Han、 Apologies for the delay in answering this post, as I was discussing the same with our team internally on this. Please find the below information related to your query:
You currently need the AIP add-in, which only supports Office applications. Office native will soon support this feature without the add-in.
In theory Adobe could write their MIP functionality to support Track and Revoke (T&R) as well.
Please note, attachments do NOT inherit labels. If you apply a non-protection label to an email the attachments do not get that. If you apply protection to a message, either by label or just manually setting Do Not Forward (DNF) or Encrypt Only (EO) , the attachment will get the protection.
For Outlook attachments, if Outlook knows how to protect it, it will. No preventing that. The permissions on the message are the same that will be applied to the attachments. If you choose DNF/EO the protection applies to only those principals on the To/Cc/Bcc lines. If you apply a label on a message that grants permissions to specific principals that is what is set on the attachments.
If Outlook sets the permissions on the attachments they get exactly what applied to the message. That is just how it works.
Let me know if you have any further questions, feel free to post back.
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