Configuration Settings document - MIME - Conversion Options - General tab
When a user sends a message in Notes rich text format and selects the Return Receipt delivery option, the IBM® Lotus® Notes® client adds the Notes ReturnReceipt item to the message. When the message recipient is also a Notes user, upon opening the message the recipient's Notes client detects the ReturnReceipt item and returns an automatic reply (a receipt) to notify the sender that the message was viewed.

By default, when a Notes rich text message is converted to MIME format for SMTP transfer, this notification mechanism fails, because MIME messages use a different item in the message header to identify return receipt requests. Similarly, when IBM® Lotus® Domino™ converts an inbound MIME message containing a return receipt request to Notes format, the return receipt information in the original MIME message is lost.

For return receipts to work when converting messages in Notes rich text format to MIME and vice-versa, set up Domino to translate between the two formats by completing these fields:
FieldEnter
Return ReceiptsChoose one:
  • Enabled - When converting messages between Notes rich text and MIME formats, Domino converts return receipt requests in the message.
  • Disabled - Domino does not preserve return receipts request in messages during conversion between Notes rich text and MIME formats.
Return Receipt MappingChoose one:
  • Use Disposition-Notification-To - When converting an outbound Notes message that includes a return receipt request into MIME format, the server converts the Notes ReturnReceipt item into the MIME header item Disposition-Notification-To.
  • Use Return-Receipt-To - When converting an outbound Notes message that includes a return receipt request into MIME format, the server converts the Notes ReturnReceipt item into the MIME header item Return-Receipt-To.
Note This field appears only if you enable Return Receipts.