diff --git a/src/drivers/drv_mixer.h b/src/drivers/drv_mixer.h
index 7c79c9e66a..317eb33942 100644
--- a/src/drivers/drv_mixer.h
+++ b/src/drivers/drv_mixer.h
@@ -65,8 +65,7 @@
 #define _MIXERIOCBASE		(0x2500)
 #define _MIXERIOC(_n)		(_PX4_IOC(_MIXERIOCBASE, _n))
 
-/** get the number of mixable outputs */
-#define MIXERIOCGETOUTPUTCOUNT	_MIXERIOC(0)
+/* _MIXERIOC(0) was deprecated */
 
 /** reset (clear) the mixer configuration */
 #define MIXERIOCRESET		_MIXERIOC(1)
diff --git a/src/drivers/dshot/dshot.cpp b/src/drivers/dshot/dshot.cpp
index fc28af3d2a..2c5f6e47c8 100644
--- a/src/drivers/dshot/dshot.cpp
+++ b/src/drivers/dshot/dshot.cpp
@@ -877,7 +877,6 @@ DShotOutput::pwm_ioctl(file *filp, int cmd, unsigned long arg)
 
 	switch (cmd) {
 	case PWM_SERVO_GET_COUNT:
-	case MIXERIOCGETOUTPUTCOUNT:
 		switch (_mode) {
 
 #if defined(BOARD_HAS_PWM) && BOARD_HAS_PWM >= 14
diff --git a/src/drivers/mkblctrl/mkblctrl.cpp b/src/drivers/mkblctrl/mkblctrl.cpp
index c11a0b5e2c..2d1a94e4a7 100644
--- a/src/drivers/mkblctrl/mkblctrl.cpp
+++ b/src/drivers/mkblctrl/mkblctrl.cpp
@@ -1028,7 +1028,6 @@ MK::pwm_ioctl(file *filp, int cmd, unsigned long arg)
 		break;
 
 	case PWM_SERVO_GET_COUNT:
-	case MIXERIOCGETOUTPUTCOUNT:
 		*(unsigned *)arg = _num_outputs;
 		break;
 
diff --git a/src/drivers/pwm_out_sim/PWMSim.cpp b/src/drivers/pwm_out_sim/PWMSim.cpp
index cb9acb84d2..86d2f57cdd 100644
--- a/src/drivers/pwm_out_sim/PWMSim.cpp
+++ b/src/drivers/pwm_out_sim/PWMSim.cpp
@@ -207,7 +207,6 @@ PWMSim::ioctl(device::file_t *filp, int cmd, unsigned long arg)
 		}
 
 	case PWM_SERVO_GET_COUNT:
-	case MIXERIOCGETOUTPUTCOUNT:
 		*(unsigned *)arg = OutputModuleInterface::MAX_ACTUATORS;
 		break;
 
diff --git a/src/drivers/px4fmu/fmu.cpp b/src/drivers/px4fmu/fmu.cpp
index acd521c013..95e7c0ae78 100644
--- a/src/drivers/px4fmu/fmu.cpp
+++ b/src/drivers/px4fmu/fmu.cpp
@@ -1277,7 +1277,6 @@ PX4FMU::pwm_ioctl(file *filp, int cmd, unsigned long arg)
 		break;
 
 	case PWM_SERVO_GET_COUNT:
-	case MIXERIOCGETOUTPUTCOUNT:
 		switch (_mode) {
 
 #if defined(BOARD_HAS_PWM) && BOARD_HAS_PWM >= 14
diff --git a/src/drivers/px4io/px4io.cpp b/src/drivers/px4io/px4io.cpp
index 686c3e45b8..eb736b57b2 100644
--- a/src/drivers/px4io/px4io.cpp
+++ b/src/drivers/px4io/px4io.cpp
@@ -2810,10 +2810,6 @@ PX4IO::ioctl(file *filep, int cmd, unsigned long arg)
 		}
 		break;
 
-	case MIXERIOCGETOUTPUTCOUNT:
-		*(unsigned *)arg = _max_actuators;
-		break;
-
 	case MIXERIOCRESET:
 		ret = 0;	/* load always resets */
 		break;
diff --git a/src/drivers/uavcan/uavcan_main.cpp b/src/drivers/uavcan/uavcan_main.cpp
index 4b080a62bc..e9ad5eeaef 100644
--- a/src/drivers/uavcan/uavcan_main.cpp
+++ b/src/drivers/uavcan/uavcan_main.cpp
@@ -828,10 +828,6 @@ UavcanNode::ioctl(file *filp, int cmd, unsigned long arg)
 		// these are no-ops, as no safety switch
 		break;
 
-	case MIXERIOCGETOUTPUTCOUNT:
-		*(unsigned *)arg = _output_count;
-		break;
-
 	case MIXERIOCRESET:
 		_mixing_interface.mixingOutput().resetMixerThreadSafe();