diff --git a/libraries/libstratosphere/include/stratosphere/psc/sf/psc_sf_i_pm_module.hpp b/libraries/libstratosphere/include/stratosphere/psc/sf/psc_sf_i_pm_module.hpp
index bf2e86a..5673bd4 100644
--- a/libraries/libstratosphere/include/stratosphere/psc/sf/psc_sf_i_pm_module.hpp
+++ b/libraries/libstratosphere/include/stratosphere/psc/sf/psc_sf_i_pm_module.hpp
@@ -43,7 +43,7 @@
                 MAKE_SERVICE_COMMAND_META(GetRequest),
                 MAKE_SERVICE_COMMAND_META(Acknowledge),
                 MAKE_SERVICE_COMMAND_META(Finalize),
-                MAKE_SERVICE_COMMAND_META(AcknowledgeEx, hos::Version_6_0_0), /* TODO: This is really 5.1.0... */
+                MAKE_SERVICE_COMMAND_META(AcknowledgeEx, hos::Version_5_1_0),
             };
     };
 
diff --git a/libraries/libstratosphere/source/psc/psc_pm_module.os.horizon.cpp b/libraries/libstratosphere/source/psc/psc_pm_module.os.horizon.cpp
index 22d947a..146e5e4 100644
--- a/libraries/libstratosphere/source/psc/psc_pm_module.os.horizon.cpp
+++ b/libraries/libstratosphere/source/psc/psc_pm_module.os.horizon.cpp
@@ -60,7 +60,7 @@
         R_ABORT_UNLESS(res);
         R_UNLESS(this->initialized, psc::ResultNotInitialized());
 
-        if (hos::GetVersion() >= hos::Version_6_0_0) {
+        if (hos::GetVersion() >= hos::Version_5_1_0) {
             return this->intf->AcknowledgeEx(state);
         } else {
             return this->intf->Acknowledge();