To create an acknowledgement letter for your donations, do the following:
In Step 1 of the letter creation process, choose Transactions for your filter audience.
In Step 2, set the letter's Purpose to Acknowledgment.
In Bloomerang CRM, only the Acknowledgement Purpose will flip a transaction's Acknowledged? flag to Yes. The interactions for the acknowledgement letters will be linked to the transactions being acknowledged.
Letters with a purpose of "Receipt" do not affect the Acknowledgement flag on a transaction.