diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3706ced..43ef8fc 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Bump allowed `spacepackets` to >=0.30, <=0.31
 - Transition CRC library from `crcmod` to `fastcrc`
 
+## Removed
+
+- `TransactionStep.SENDING_ACK_OF_FINISHED` for source handler which is not required anymore.
+
 # [v0.5.1] 2025-02-10
 
 - Bump allowed `spacepackets` to v0.28.0
diff --git a/src/cfdppy/handler/source.py b/src/cfdppy/handler/source.py
index 4a320bd..4ad24e0 100644
--- a/src/cfdppy/handler/source.py
+++ b/src/cfdppy/handler/source.py
@@ -91,7 +91,6 @@ class TransactionStep(enum.Enum):
     SENDING_EOF = 6
     WAITING_FOR_EOF_ACK = 7
     WAITING_FOR_FINISHED = 8
-    SENDING_ACK_OF_FINISHED = 9
     NOTICE_OF_COMPLETION = 10
 
 
@@ -789,9 +788,7 @@ def _handle_wait_for_finish(self, packet_holder: PduHolder) -> None:
         self._params.finished_params = finished_pdu.finished_params
         if self.transmission_mode == TransmissionMode.ACKNOWLEDGED:
             self._prepare_finished_ack_packet(finished_pdu.condition_code)
-            self.states.step = TransactionStep.SENDING_ACK_OF_FINISHED
-        else:
-            self.states.step = TransactionStep.NOTICE_OF_COMPLETION
+        self.states.step = TransactionStep.NOTICE_OF_COMPLETION
 
     def _notice_of_completion(self) -> None:
         if self.cfg.indication_cfg.transaction_finished_indication_required:
@@ -822,8 +819,6 @@ def _fsm_advancement_after_packets_were_sent(self) -> None:
             self.states.step = self._params.ack_params.step_before_retransmission
         elif self.states.step == TransactionStep.SENDING_FILE_DATA:
             self._handle_file_data_sent()
-        elif self.states.step == TransactionStep.SENDING_ACK_OF_FINISHED:
-            self.states.step = TransactionStep.NOTICE_OF_COMPLETION
 
     def _handle_eof_sent(self, cancel_eof: bool) -> None:
         if self.transmission_mode == TransmissionMode.ACKNOWLEDGED:
diff --git a/tests/test_src_handler_acked.py b/tests/test_src_handler_acked.py
index d1faef8..842827a 100644
--- a/tests/test_src_handler_acked.py
+++ b/tests/test_src_handler_acked.py
@@ -241,7 +241,7 @@ def _generic_acked_transfer_completion(
         )
         pdu_conf = eof_pdu.pdu_header.pdu_conf
         self._insert_eof_ack_packet(eof_pdu)
-        self._insert_finished_pdu(pdu_conf)
+        self._insert_finished_pdu(pdu_conf, 1)
         self._acknowledge_finished_pdu(pdu_conf)
         self.source_handler.state_machine()
         self._verify_transaction_finished_indication(transaction_id, expected_finished_params)
@@ -253,7 +253,7 @@ def _generic_acked_transfer_completion(
             TransactionStep.IDLE,
         )
 
-    def _insert_finished_pdu(self, pdu_conf: PduConfig):
+    def _insert_finished_pdu(self, pdu_conf: PduConfig, expected_num_of_packets: int):
         finished_pdu = FinishedPdu(
             pdu_conf,
             FinishedParams(
@@ -265,9 +265,9 @@ def _insert_finished_pdu(self, pdu_conf: PduConfig):
         self.source_handler.state_machine(finished_pdu)
         self._state_checker(
             None,
-            True,
-            CfdpState.BUSY,
-            TransactionStep.SENDING_ACK_OF_FINISHED,
+            expected_num_of_packets,
+            CfdpState.IDLE,
+            TransactionStep.IDLE,
         )
 
     def _verify_eof_pdu_for_positive_ack(self, expected_eof: EofPdu, expected_ack_counter: int):