edd_set_payment_transaction_id()

The 
edd_set_payment_transaction_id() function is used to set the transaction ID related to a specific purchase.

The function takes two parameters, one for the payment ID and one for the transaction ID:

edd_set_payment_transaction_id( $payment_id, $transaction_id );

The transaction ID is passed through a filter called 
edd_set_payment_transaction_id, which receives two parameters:

• $transaction_id
• $payment_id

Transaction ID tracking was implemented in EDD v2.1.