diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.md b/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.md
index 2222b8cf25..00ea688bb8 100644
--- a/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.md
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.md
@@ -96,6 +96,18 @@ Verify that the subscription returned by the DSS via the search is correctly for
 
 Verify that the version field is as expected.
 
+### Attempt Subscription mutation with incorrect version test step
+
+This test step attempts to mutate the subscription both with a missing and incorrect OVN, and checks that the DSS reacts properly.
+
+#### 🛑 Mutation with empty version fails check
+
+If a request to mutate a subscription is missing the version and succeeds, the DSS is failing to properly implement **[astm.f3548.v21.DSS0005,5](../../../../requirements/astm/f3548/v21.md)**.
+
+#### 🛑 Mutation with incorrect version fails check
+
+If a request to mutate a subscription providing the wrong version succeeds, the DSS is failing to properly implement **[astm.f3548.v21.DSS0005,5](../../../../requirements/astm/f3548/v21.md)**.
+
 ### Mutate Subscription test step
 
 This test step mutates the previously created subscription to verify that the DSS reacts properly: notably, it checks that the subscription version is updated,
diff --git a/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.py b/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.py
index e0f8f9c57a..d60fe8b876 100644
--- a/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.py
+++ b/monitoring/uss_qualifier/scenarios/astm/utm/dss/subscription_simple.py
@@ -124,6 +124,10 @@ def run(self, context: ExecutionContext):
         self._create_and_validate_subs()
         self.end_test_step()
 
+        self.begin_test_step("Attempt Subscription mutation with incorrect version")
+        self._test_mutate_subscription_version_check()
+        self.end_test_step()
+
         self.begin_test_step("Mutate Subscription")
         self._test_mutate_subscriptions_shift_time()
         self._test_mutate_subscriptions_change_area()
@@ -277,6 +281,46 @@ def _compare_upsert_resp_with_params(
             query_timestamps=[creation_resp_under_test.request.timestamp],
         )
 
+    def _test_mutate_subscription_version_check(self):
+        """Attempt to mutate a subscription while providing a missing and incorrect OVN"""
+        orig_params = self._sub_params_by_sub_id[self._base_sub_id].copy()
+        sub = self._current_subscriptions[self._base_sub_id]
+        new_params = SubscriptionParams(
+            sub_id=self._base_sub_id,
+            area_vertices=orig_params.area_vertices,
+            min_alt_m=orig_params.min_alt_m,
+            max_alt_m=orig_params.max_alt_m,
+            start_time=sub.time_start.value.datetime + timedelta(seconds=10),
+            end_time=sub.time_end.value.datetime + timedelta(seconds=10),
+            base_url=orig_params.base_url,
+            notify_for_op_intents=orig_params.notify_for_op_intents,
+            notify_for_constraints=orig_params.notify_for_constraints,
+        )
+
+        with self.check("Mutation with empty version fails", self._pid) as check:
+            no_version_res = self._dss.upsert_subscription(
+                version="",
+                **new_params,
+            )
+            if no_version_res.status_code not in [400, 409]:
+                check.record_failed(
+                    "Mutation with empty version did not fail as expected",
+                    details=f"Mutation with an empty version is expected , received status code {no_version_res.status_code}",
+                    query_timestamps=[no_version_res.request.timestamp],
+                )
+
+        with self.check("Mutation with incorrect version fails", self._pid) as check:
+            wrong_version_res = self._dss.upsert_subscription(
+                version="ThisIsAnIncorrectVersion",
+                **new_params,
+            )
+            if wrong_version_res.status_code not in [400, 409]:
+                check.record_failed(
+                    "Mutation with incorrect version did not fail as expected",
+                    details=f"Mutation with an incorrect version is expected , received status code {wrong_version_res.status_code}",
+                    query_timestamps=[wrong_version_res.request.timestamp],
+                )
+
     def _test_mutate_subscriptions_shift_time(self):
         """Mutate all existing subscriptions by adding 10 seconds to their start and end times"""