diff --git a/ArduCopter/Copter.cpp b/ArduCopter/Copter.cpp
index 43c6d2bb759f4..03448c07b3f5f 100644
--- a/ArduCopter/Copter.cpp
+++ b/ArduCopter/Copter.cpp
@@ -164,7 +164,9 @@ const AP_Scheduler::Task Copter::scheduler_tasks[] = {
     SCHED_TASK_CLASS(ToyMode,              &copter.g2.toy_mode,         update,          10,  50,  24),
 #endif
     SCHED_TASK(auto_disarm_check,     10,     50,  27),
-    SCHED_TASK(auto_trim,             10,     75,  30),
+#if AP_COPTER_AHRS_AUTO_TRIM_ENABLED
+    SCHED_TASK_CLASS(RC_Channels_Copter,   &copter.g2.rc_channels,      auto_trim_run,   10,  75,  30),
+#endif
 #if AP_RANGEFINDER_ENABLED
     SCHED_TASK(read_rangefinder,      20,    100,  33),
 #endif
diff --git a/ArduCopter/Copter.h b/ArduCopter/Copter.h
index eaa65fb82024d..75461d9ccc217 100644
--- a/ArduCopter/Copter.h
+++ b/ArduCopter/Copter.h
@@ -496,10 +496,6 @@ class Copter : public AP_Vehicle {
     // arm_time_ms - Records when vehicle was armed. Will be Zero if we are disarmed.
     uint32_t arm_time_ms;
 
-    // Used to exit the roll and pitch auto trim function
-    uint8_t auto_trim_counter;
-    bool auto_trim_started = false;
-
     // Camera
 #if AP_CAMERA_ENABLED
     AP_Camera camera{MASK_LOG_CAMERA};
@@ -997,11 +993,6 @@ class Copter : public AP_Vehicle {
     // takeoff_check.cpp
     void takeoff_check();
 
-    // RC_Channel.cpp
-    void save_trim();
-    void auto_trim();
-    void auto_trim_cancel();
-
     // system.cpp
     void init_ardupilot() override;
     void startup_INS_ground();
diff --git a/ArduCopter/RC_Channel_Copter.cpp b/ArduCopter/RC_Channel_Copter.cpp
index ee2fe1c82be8e..b09ae572e5187 100644
--- a/ArduCopter/RC_Channel_Copter.cpp
+++ b/ArduCopter/RC_Channel_Copter.cpp
@@ -213,7 +213,7 @@ bool RC_Channel_Copter::do_aux_function(const AuxFuncTrigger &trigger)
             if ((ch_flag == AuxSwitchPos::HIGH) &&
                 (copter.flightmode->allows_save_trim()) &&
                 (copter.channel_throttle->get_control_in() == 0)) {
-                copter.save_trim();
+                copter.g2.rc_channels.save_trim();
             }
             break;
 
@@ -631,6 +631,12 @@ bool RC_Channel_Copter::do_aux_function(const AuxFuncTrigger &trigger)
             break;
 #endif
 
+#if AP_COPTER_AHRS_AUTO_TRIM_ENABLED
+        case AUX_FUNC::AHRS_AUTO_TRIM:
+            copter.g2.rc_channels.do_aux_function_ahrs_auto_trim(ch_flag);
+            break;
+#endif  // AP_COPTER_AHRS_AUTO_TRIM_ENABLED
+
         case AUX_FUNC::SIMPLE_HEADING_RESET:
             if (ch_flag == AuxSwitchPos::HIGH) {
                 copter.init_simple_bearing();
@@ -706,68 +712,78 @@ void RC_Channel_Copter::do_aux_function_change_force_flying(const AuxSwitchPos c
     }
 }
 
+// note that this is a method on the RC_Channels object, not the
+// individual channel
 // save_trim - adds roll and pitch trims from the radio to ahrs
-void Copter::save_trim()
+void RC_Channels_Copter::save_trim()
 {
     // save roll and pitch trim
-    float roll_trim = ToRad((float)channel_roll->get_control_in()*0.01f);
-    float pitch_trim = ToRad((float)channel_pitch->get_control_in()*0.01f);
-    ahrs.add_trim(roll_trim, pitch_trim);
+    float roll_trim = ToRad((float)get_roll_channel().get_control_in()*0.01f);
+    float pitch_trim = ToRad((float)get_pitch_channel().get_control_in()*0.01f);
+    AP::ahrs().add_trim(roll_trim, pitch_trim);
     LOGGER_WRITE_EVENT(LogEvent::SAVE_TRIM);
     gcs().send_text(MAV_SEVERITY_INFO, "Trim saved");
 }
 
+#if AP_COPTER_AHRS_AUTO_TRIM_ENABLED
+// start/stop ahrs auto trim
+void RC_Channels_Copter::do_aux_function_ahrs_auto_trim(const RC_Channel::AuxSwitchPos ch_flag)
+{
+    switch (ch_flag) {
+    case RC_Channel::AuxSwitchPos::HIGH:
+        gcs().send_text(MAV_SEVERITY_INFO, "AutoTrim running");
+        // flash the leds
+        AP_Notify::flags.save_trim = true;
+        auto_trim.running = true;
+        break;
+    case RC_Channel::AuxSwitchPos::MIDDLE:
+        break;
+    case RC_Channel::AuxSwitchPos::LOW:
+        if (auto_trim.running) {
+            AP_Notify::flags.save_trim = false;
+            save_trim();
+        }
+        break;
+    }
+}
+
 // auto_trim - slightly adjusts the ahrs.roll_trim and ahrs.pitch_trim towards the current stick positions
 // meant to be called continuously while the pilot attempts to keep the copter level
-void Copter::auto_trim_cancel()
+void RC_Channels_Copter::auto_trim_cancel()
 {
-    auto_trim_counter = 0;
+    auto_trim.running = false;
     AP_Notify::flags.save_trim = false;
     gcs().send_text(MAV_SEVERITY_INFO, "AutoTrim cancelled");
+    // restore original trims
 }
 
-void Copter::auto_trim()
+void RC_Channels_Copter::auto_trim_run()
 {
-    if (auto_trim_counter > 0) {
-        if (copter.flightmode != &copter.mode_stabilize ||
-            !copter.motors->armed()) {
-            auto_trim_cancel();
+        if (!auto_trim.running) {
             return;
         }
 
-        // flash the leds
-        AP_Notify::flags.save_trim = true;
-
-        if (!auto_trim_started) {
-            if (ap.land_complete) {
-                // haven't taken off yet
-                return;
-            }
-            auto_trim_started = true;
+        // only trim in certain modes:
+        if (copter.flightmode != &copter.mode_stabilize &&
+            copter.flightmode != &copter.mode_althold) {
+            auto_trim_cancel();
+            return;
         }
 
-        if (ap.land_complete) {
-            // landed again.
+        // must be started and stopped mid-air:
+        if (copter.ap.land_complete_maybe) {
             auto_trim_cancel();
             return;
         }
 
-        auto_trim_counter--;
-
         // calculate roll trim adjustment
-        float roll_trim_adjustment = ToRad((float)channel_roll->get_control_in() / 4000.0f);
+        float roll_trim_adjustment = ToRad((float)get_roll_channel().get_control_in() / 4000.0f);
 
         // calculate pitch trim adjustment
-        float pitch_trim_adjustment = ToRad((float)channel_pitch->get_control_in() / 4000.0f);
-
-        // add trim to ahrs object
-        // save to eeprom on last iteration
-        ahrs.add_trim(roll_trim_adjustment, pitch_trim_adjustment, (auto_trim_counter == 0));
+        float pitch_trim_adjustment = ToRad((float)get_pitch_channel().get_control_in() / 4000.0f);
 
-        // on last iteration restore leds and accel gains to normal
-        if (auto_trim_counter == 0) {
-            AP_Notify::flags.save_trim = false;
-            gcs().send_text(MAV_SEVERITY_INFO, "AutoTrim: Trims saved");
-        }
-    }
+        // add trim to ahrs object, but do not save to permanent storage:
+        AP::ahrs().add_trim(roll_trim_adjustment, pitch_trim_adjustment, false);
 }
+
+#endif  // AP_COPTER_AHRS_AUTO_TRIM_ENABLED
diff --git a/ArduCopter/RC_Channel_Copter.h b/ArduCopter/RC_Channel_Copter.h
index 07bf285ab59a6..5a4be076d5671 100644
--- a/ArduCopter/RC_Channel_Copter.h
+++ b/ArduCopter/RC_Channel_Copter.h
@@ -46,6 +46,18 @@ class RC_Channels_Copter : public RC_Channels
     // returns true if throttle arming checks should be run
     bool arming_check_throttle() const override;
 
+    // support for trimming AHRS using RC stick inputs, enabled via an
+    // aux function
+#if AP_COPTER_AHRS_AUTO_TRIM_ENABLED
+    void do_aux_function_ahrs_auto_trim(const RC_Channel::AuxSwitchPos ch_flag);
+    struct {
+        bool running;
+    } auto_trim;
+    void auto_trim_run();
+    void auto_trim_cancel();
+#endif  // AP_COPTER_AHRS_AUTO_TRIM_ENABLED
+    void save_trim();
+
 protected:
 
     int8_t flight_mode_channel_number() const override;
diff --git a/ArduCopter/config.h b/ArduCopter/config.h
index 0da560ea09099..8e2bf0e8838f4 100644
--- a/ArduCopter/config.h
+++ b/ArduCopter/config.h
@@ -578,6 +578,10 @@
 # define AP_COPTER_ADVANCED_FAILSAFE_ENABLED 0
 #endif
 
+#ifndef AP_COPTER_AHRS_AUTO_TRIM_ENABLED
+# define AP_COPTER_AHRS_AUTO_TRIM_ENABLED 1
+#endif
+
 #ifndef CH_MODE_DEFAULT
  # define CH_MODE_DEFAULT   5
 #endif
diff --git a/ArduCopter/motors.cpp b/ArduCopter/motors.cpp
index 0b2193107ffca..552baa6faee9c 100644
--- a/ArduCopter/motors.cpp
+++ b/ArduCopter/motors.cpp
@@ -2,7 +2,6 @@
 
 #define ARM_DELAY               20  // called at 10hz so 2 seconds
 #define DISARM_DELAY            20  // called at 10hz so 2 seconds
-#define AUTO_TRIM_DELAY         100 // called at 10hz so 10 seconds
 #define LOST_VEHICLE_DELAY      10  // called at 10hz so 1 second
 
 static uint32_t auto_disarm_begin;
@@ -39,7 +38,7 @@ void Copter::arm_motors_check()
     if (yaw_in > 4000) {
 
         // increase the arming counter to a maximum of 1 beyond the auto trim counter
-        if (arming_counter <= AUTO_TRIM_DELAY) {
+        if (arming_counter < ARM_DELAY) {
             arming_counter++;
         }
 
@@ -51,15 +50,6 @@ void Copter::arm_motors_check()
             }
         }
 
-        // arm the motors and configure for flight
-        if (arming_counter == AUTO_TRIM_DELAY && motors->armed() && flightmode->mode_number() == Mode::Number::STABILIZE) {
-            gcs().send_text(MAV_SEVERITY_INFO, "AutoTrim start");
-            auto_trim_counter = 250;
-            auto_trim_started = false;
-            // ensure auto-disarm doesn't trigger immediately
-            auto_disarm_begin = millis();
-        }
-
     // full left and rudder disarming is enabled
     } else if ((yaw_in < -4000) && (arming_rudder == AP_Arming::RudderArming::ARMDISARM)) {
         if (!flightmode->has_manual_throttle() && !ap.land_complete) {
diff --git a/Blimp/Blimp.h b/Blimp/Blimp.h
index 596c81e547759..fb3499e532193 100644
--- a/Blimp/Blimp.h
+++ b/Blimp/Blimp.h
@@ -239,10 +239,6 @@ class Blimp : public AP_Vehicle
     // arm_time_ms - Records when vehicle was armed. Will be Zero if we are disarmed.
     uint32_t arm_time_ms;
 
-    // Used to exit the roll and pitch auto trim function
-    uint8_t auto_trim_counter;
-    bool auto_trim_started = false;
-
     // last valid RC input time
     uint32_t last_radio_update_ms;
 
@@ -412,11 +408,6 @@ class Blimp : public AP_Vehicle
     bool rangefinder_alt_ok();
     bool rangefinder_up_ok();
 
-    // RC_Channel.cpp
-    void save_trim();
-    void auto_trim();
-    void auto_trim_cancel();
-
     // system.cpp
     void init_ardupilot() override;
     void startup_INS_ground();
diff --git a/Blimp/RC_Channel_Blimp.cpp b/Blimp/RC_Channel_Blimp.cpp
index 5db884f88a25e..20e68927d38cc 100644
--- a/Blimp/RC_Channel_Blimp.cpp
+++ b/Blimp/RC_Channel_Blimp.cpp
@@ -106,14 +106,6 @@ bool RC_Channel_Blimp::do_aux_function(const AuxFuncTrigger &trigger)
 
     switch (ch_option) {
 
-    case AUX_FUNC::SAVE_TRIM:
-        if ((ch_flag == AuxSwitchPos::HIGH) &&
-            (blimp.control_mode <= Mode::Number::MANUAL) &&
-            (blimp.channel_up->get_control_in() == 0)) {
-            blimp.save_trim();
-        }
-        break;
-
     case AUX_FUNC::LOITER:
         do_aux_function_change_mode(Mode::Number::LOITER, ch_flag);
         break;
@@ -127,69 +119,3 @@ bool RC_Channel_Blimp::do_aux_function(const AuxFuncTrigger &trigger)
     }
     return true;
 }
-
-// save_trim - adds roll and pitch trims from the radio to ahrs
-void Blimp::save_trim()
-{
-    // save roll and pitch trim
-    float roll_trim = ToRad((float)channel_right->get_control_in()*0.01f);
-    float pitch_trim = ToRad((float)channel_front->get_control_in()*0.01f);
-    ahrs.add_trim(roll_trim, pitch_trim);
-    LOGGER_WRITE_EVENT(LogEvent::SAVE_TRIM);
-    gcs().send_text(MAV_SEVERITY_INFO, "Trim saved");
-}
-
-// auto_trim - slightly adjusts the ahrs.roll_trim and ahrs.pitch_trim towards the current stick positions
-// meant to be called continuously while the pilot attempts to keep the blimp level
-void Blimp::auto_trim_cancel()
-{
-    auto_trim_counter = 0;
-    AP_Notify::flags.save_trim = false;
-    gcs().send_text(MAV_SEVERITY_INFO, "AutoTrim cancelled");
-}
-
-void Blimp::auto_trim()
-{
-    if (auto_trim_counter > 0) {
-        if (blimp.flightmode != &blimp.mode_manual ||
-            !blimp.motors->armed()) {
-            auto_trim_cancel();
-            return;
-        }
-
-        // flash the leds
-        AP_Notify::flags.save_trim = true;
-
-        if (!auto_trim_started) {
-            if (ap.land_complete) {
-                // haven't taken off yet
-                return;
-            }
-            auto_trim_started = true;
-        }
-
-        if (ap.land_complete) {
-            // landed again.
-            auto_trim_cancel();
-            return;
-        }
-
-        auto_trim_counter--;
-
-        // calculate roll trim adjustment
-        float roll_trim_adjustment = ToRad((float)channel_right->get_control_in() / 4000.0f);
-
-        // calculate pitch trim adjustment
-        float pitch_trim_adjustment = ToRad((float)channel_front->get_control_in() / 4000.0f);
-
-        // add trim to ahrs object
-        // save to eeprom on last iteration
-        ahrs.add_trim(roll_trim_adjustment, pitch_trim_adjustment, (auto_trim_counter == 0));
-
-        // on last iteration restore leds and accel gains to normal
-        if (auto_trim_counter == 0) {
-            AP_Notify::flags.save_trim = false;
-            gcs().send_text(MAV_SEVERITY_INFO, "AutoTrim: Trims saved");
-        }
-    }
-}
diff --git a/Blimp/motors.cpp b/Blimp/motors.cpp
index 90fb3308a925b..d2e6cfe7d2bd2 100644
--- a/Blimp/motors.cpp
+++ b/Blimp/motors.cpp
@@ -2,7 +2,6 @@
 
 #define ARM_DELAY               20  // called at 10hz so 2 seconds
 #define DISARM_DELAY            20  // called at 10hz so 2 seconds
-#define AUTO_TRIM_DELAY         100 // called at 10hz so 10 seconds
 #define LOST_VEHICLE_DELAY      10  // called at 10hz so 1 second
 
 // arm_motors_check - checks for pilot input to arm or disarm the blimp
@@ -29,7 +28,7 @@ void Blimp::arm_motors_check()
     if (yaw_in > 900) {
 
         // increase the arming counter to a maximum of 1 beyond the auto trim counter
-        if (arming_counter <= AUTO_TRIM_DELAY) {
+        if (arming_counter < ARM_DELAY) {
             arming_counter++;
         }
 
@@ -41,13 +40,6 @@ void Blimp::arm_motors_check()
             }
         }
 
-        // arm the motors and configure for flight
-        if (arming_counter == AUTO_TRIM_DELAY && motors->armed() && control_mode == Mode::Number::MANUAL) {
-            gcs().send_text(MAV_SEVERITY_INFO, "AutoTrim start");
-            auto_trim_counter = 250;
-            auto_trim_started = false;
-        }
-
         // full left and rudder disarming is enabled
     } else if ((yaw_in < -900) && (arming_rudder == AP_Arming::RudderArming::ARMDISARM)) {
         if (!flightmode->has_manual_throttle() && !ap.land_complete) {
diff --git a/Tools/AP_Bootloader/board_types.txt b/Tools/AP_Bootloader/board_types.txt
index c83fe967a3f50..dadc1ed9161ac 100755
--- a/Tools/AP_Bootloader/board_types.txt
+++ b/Tools/AP_Bootloader/board_types.txt
@@ -300,6 +300,7 @@ AP_HW_FlywooF405HD_AIOv2             1180
 AP_HW_FlywooH743Pro                  1181
 AP_HW_CBU_StampH743_LC               1182
 AP_HW_NarinH7                        1183
+AP_HW_BrahmaF4                       1184
 
 AP_HW_JFB200                         1200
 
diff --git a/Tools/ardupilotwaf/boards.py b/Tools/ardupilotwaf/boards.py
index df78bc533fd11..388495c4f8283 100644
--- a/Tools/ardupilotwaf/boards.py
+++ b/Tools/ardupilotwaf/boards.py
@@ -287,7 +287,7 @@ def configure_env(self, cfg, env):
                 '-Wno-gnu-variable-sized-type-not-at-end',
                 '-Werror=implicit-fallthrough',
                 '-cl-single-precision-constant',
-                '-Wno-vla-cxx-extension',
+                '-Wno-vla-extension',
             ]
         else:
             env.CFLAGS += [
@@ -420,7 +420,7 @@ def configure_env(self, cfg, env):
 
                 '-Wno-gnu-designator',
                 '-Wno-mismatched-tags',
-                '-Wno-vla-cxx-extension',
+                '-Wno-vla-extension',
                 '-Wno-gnu-variable-sized-type-not-at-end',
                 '-Werror=implicit-fallthrough',
                 '-cl-single-precision-constant',
diff --git a/Tools/autotest/arducopter.py b/Tools/autotest/arducopter.py
index 994b47a053fa1..677db76d2dd61 100644
--- a/Tools/autotest/arducopter.py
+++ b/Tools/autotest/arducopter.py
@@ -12542,6 +12542,8 @@ def CompassLearnCopyFromEKF(self):
             'COMPASS_USE3': 0,
         })
         self.assert_parameter_value("COMPASS_OFS_X", 20, epsilon=30)
+        # set the parameter so it gets reset at context pop time:
+        self.set_parameter("COMPASS_OFS_X", 20)
         new_compass_ofs_x = 200
         self.set_parameters({
             "SIM_MAG1_OFS_X": new_compass_ofs_x,
@@ -12574,6 +12576,89 @@ def CompassLearnCopyFromEKF(self):
         self.reboot_sitl()
         self.assert_parameter_value("COMPASS_OFS_X", new_compass_ofs_x, epsilon=30)
 
+    def AHRSAutoTrim(self):
+        '''calibrate AHRS trim using RC input'''
+        self.progress("Making earth frame same as body frame")  # because I'm lazy
+        self.takeoff(5, mode='GUIDED')
+        self.guided_achieve_heading(0)
+        self.do_land()
+
+        self.set_parameters({
+            'RC9_OPTION': 182,
+        })
+
+        param_last_check_time = 0
+        for mode in ['STABILIZE', 'ALT_HOLD']:
+            self.set_parameters({
+                'AHRS_TRIM_X': 0.1,
+                'AHRS_TRIM_Y': -0.1,
+            })
+            self.takeoff(mode=mode)
+            self.set_rc(9, 2000)
+            tstart = self.get_sim_time()
+            while True:
+                now = self.get_sim_time_cached()
+                if now - tstart > 30:
+                    raise ValueError(f"Failed to reduce trims in {mode}!")
+                lpn = self.assert_receive_message('LOCAL_POSITION_NED')
+                delta = 40
+                roll_input = 1500
+                if lpn.vx > 0:
+                    roll_input -= delta
+                elif lpn.vx < 0:
+                    roll_input += delta
+
+                pitch_input = 1500
+                if lpn.vy > 0:
+                    pitch_input += delta
+                elif lpn.vy < 0:
+                    pitch_input -= delta
+                self.set_rc_from_map({
+                    1: roll_input,
+                    2: pitch_input,
+                }, quiet=True)
+
+                # check parameters once/second:
+                if now - param_last_check_time > 1:
+                    param_last_check_time = now
+                    trim_x = self.get_parameter('AHRS_TRIM_X', verbose=False)
+                    trim_y = self.get_parameter('AHRS_TRIM_Y', verbose=False)
+                    self.progress(f"trim_x={trim_x} trim_y={trim_y}")
+                    if abs(trim_x) < 0.02 and abs(trim_y) < 0.02:
+                        self.progress("Good AHRS trims")
+                        if abs(lpn.vx) > 1 or abs(lpn.vy) > 1:
+                            raise NotAchievedException("Velocity after trimming?!")
+                        break
+            self.context_collect('STATUSTEXT')
+            self.set_rc(9, 1000)
+            self.wait_statustext('Trim saved', check_context=True)
+            self.context_stop_collecting('STATUSTEXT')
+            self.do_land()
+            self.set_rc_default()
+
+        self.progress("Landing should cancel the autotrim")
+        self.takeoff(10, mode='STABILIZE')
+        self.context_collect('STATUSTEXT')
+        self.set_rc(9, 2000)
+        self.wait_statustext('AutoTrim running', check_context=True)
+        self.do_land()
+        self.wait_statustext('AutoTrim cancelled', check_context=True)
+        self.set_rc(9, 1000)
+
+        self.progress("Changing mode to LOITER")
+        self.takeoff(10, mode='STABILIZE')
+        self.context_collect('STATUSTEXT')
+        self.set_rc(9, 2000)
+        self.wait_statustext('AutoTrim running', check_context=True)
+        self.change_mode('LOITER')
+        self.wait_statustext('AutoTrim cancelled', check_context=True)
+        self.do_land()
+        self.set_rc(9, 1000)
+
+    def do_land(self):
+        self.change_mode('LAND')
+        self.wait_disarmed()
+
     def tests2b(self):  # this block currently around 9.5mins here
         '''return list of all tests'''
         ret = ([
@@ -12685,6 +12770,7 @@ def tests2b(self):  # this block currently around 9.5mins here
             self.TestTetherStuck,
             self.ScriptingFlipMode,
             self.CompassLearnCopyFromEKF,
+            self.AHRSAutoTrim,
         ])
         return ret
 
diff --git a/Tools/autotest/rover.py b/Tools/autotest/rover.py
index fef6519a7dd82..c4be3f75075e8 100644
--- a/Tools/autotest/rover.py
+++ b/Tools/autotest/rover.py
@@ -2306,6 +2306,47 @@ def GCSFence(self):
         self.test_gcs_fence_via_mavproxy(target_system=target_system,
                                          target_component=target_component)
 
+    def GCSFenceInvalidPoint(self):
+        '''Test fetch non-existant fencepoint'''
+        target_system = 1
+        target_component = 1
+
+        here = self.mav.location()
+        self.upload_fences_from_locations([
+            (mavutil.mavlink.MAV_CMD_NAV_FENCE_POLYGON_VERTEX_EXCLUSION, [
+                # east
+                self.offset_location_ne(here, -50, 20), # bl
+                self.offset_location_ne(here, 50, 20), # br
+                self.offset_location_ne(here, 50, 40), # tr
+            ]),
+        ])
+        for i in 0, 1, 2:
+            self.assert_fetch_mission_item_int(target_system, target_component, i, mavutil.mavlink.MAV_MISSION_TYPE_FENCE)
+        self.progress("Requesting invalid point")
+        self.mav.mav.mission_request_int_send(
+            target_system,
+            target_component,
+            3,
+            mavutil.mavlink.MAV_MISSION_TYPE_FENCE
+        )
+        self.context_push()
+        self.context_collect('MISSION_COUNT')
+        m = self.assert_receive_mission_ack(
+            mavutil.mavlink.MAV_MISSION_TYPE_FENCE,
+            want_type=mavutil.mavlink.MAV_MISSION_INVALID_SEQUENCE,
+        )
+        self.delay_sim_time(0.1)
+        found = False
+        for m in self.context_collection('MISSION_COUNT'):
+            if m.mission_type != mavutil.mavlink.MAV_MISSION_TYPE_FENCE:
+                continue
+            if m.count != 3:
+                raise NotAchievedException("Unexpected count in MISSION_COUNT")
+            found = True
+        self.context_pop()
+        if not found:
+            raise NotAchievedException("Did not see correction for fencepoint count")
+
     # explode the write_type_to_storage method
     # FIXME: test converting invalid fences / minimally valid fences / normal fences
     # FIXME: show that uploading smaller items take up less space
@@ -2533,6 +2574,7 @@ def assert_receive_mission_ack(self, mission_type,
         if m.type != want_type:
             raise NotAchievedException("Expected ack type %u got %u" %
                                        (want_type, m.type))
+        return m
 
     def assert_filepath_content(self, filepath, want):
         with open(filepath) as f:
@@ -7015,6 +7057,7 @@ def tests(self):
             self.Offboard,
             self.MAVProxyParam,
             self.GCSFence,
+            self.GCSFenceInvalidPoint,
             self.GCSMission,
             self.GCSRally,
             self.MotorTest,
diff --git a/Tools/autotest/test_build_options.py b/Tools/autotest/test_build_options.py
index 5331d39c81bf5..0df65882cc8b6 100755
--- a/Tools/autotest/test_build_options.py
+++ b/Tools/autotest/test_build_options.py
@@ -290,6 +290,7 @@ def define_is_whitelisted_for_feature_in_code(self, target, define):
             feature_define_whitelist.add(r'AP_MOTORS_FRAME_.*_ENABLED')
             feature_define_whitelist.add('AP_COPTER_ADVANCED_FAILSAFE_ENABLED')
             feature_define_whitelist.add('AP_INERTIALSENSOR_FAST_SAMPLE_WINDOW_ENABLED')
+            feature_define_whitelist.add('AP_COPTER_AHRS_AUTO_TRIM_ENABLED')
 
         if target.lower() != "plane":
             # only on Plane:
diff --git a/Tools/autotest/vehicle_test_suite.py b/Tools/autotest/vehicle_test_suite.py
index daef87434f966..562f9ab6d848c 100644
--- a/Tools/autotest/vehicle_test_suite.py
+++ b/Tools/autotest/vehicle_test_suite.py
@@ -5612,7 +5612,7 @@ def rc_defaults(self):
             16: 1500,
         }
 
-    def set_rc_from_map(self, _map, timeout=20):
+    def set_rc_from_map(self, _map, timeout=20, quiet=False):
         map_copy = _map.copy()
         for v in map_copy.values():
             if not isinstance(v, int):
@@ -5639,7 +5639,8 @@ def set_rc_from_map(self, _map, timeout=20):
                     bad_channels += " (ch=%u want=%u got=%u)" % (chan, map_copy[chan], chan_pwm)
                     break
             if len(bad_channels) == 0:
-                self.progress("RC values good")
+                if not quiet:
+                    self.progress("RC values good")
                 break
             self.progress("RC values bad:%s" % bad_channels)
             if not self.rc_thread.is_alive():
@@ -9311,6 +9312,19 @@ def upload_using_mission_protocol(self, mission_type, items):
                                        (mavutil.mavlink.enums["MAV_MISSION_RESULT"][m.type].name),)
         self.progress("Upload of all %u items succeeded" % len(items))
 
+    def assert_fetch_mission_item_int(self, target_system, target_component, seq, mission_type):
+        self.mav.mav.mission_request_int_send(target_system,
+                                              target_component,
+                                              seq,
+                                              mission_type)
+        m = self.assert_receive_message(
+            'MISSION_ITEM_INT',
+            condition=f'MISSION_ITEM_INT.mission_type=={mission_type}',
+        )
+        if m is None:
+            raise NotAchievedException("Did not receive MISSION_ITEM_INT")
+        return m
+
     def download_using_mission_protocol(self, mission_type, verbose=False, timeout=10):
         '''mavlink2 required'''
         target_system = 1
@@ -9362,16 +9376,7 @@ def download_using_mission_protocol(self, mission_type, verbose=False, timeout=1
                 return items
             self.progress("Requesting item %u (remaining=%u)" %
                           (next_to_request, len(remaining_to_receive)))
-            self.mav.mav.mission_request_int_send(target_system,
-                                                  target_component,
-                                                  next_to_request,
-                                                  mission_type)
-            m = self.mav.recv_match(type='MISSION_ITEM_INT',
-                                    blocking=True,
-                                    timeout=5,
-                                    condition='MISSION_ITEM_INT.mission_type==%u' % mission_type)
-            if m is None:
-                raise NotAchievedException("Did not receive MISSION_ITEM_INT")
+            m = self.assert_fetch_mission_item_int(target_system, target_component, next_to_request, mission_type)
             if m.target_system != self.mav.source_system:
                 raise NotAchievedException("Wrong target system (want=%u got=%u)" %
                                            (self.mav.source_system, m.target_system))
diff --git a/Tools/scripts/build_options.py b/Tools/scripts/build_options.py
index d6d85d58f0a89..664d65dc70a6d 100644
--- a/Tools/scripts/build_options.py
+++ b/Tools/scripts/build_options.py
@@ -158,6 +158,7 @@ def config_option(self):
     Feature('Copter', 'MODE_FLIP', 'MODE_FLIP_ENABLED', 'Enable Mode Flip', 0, None),
     Feature('Copter', 'MODE_BRAKE', 'MODE_BRAKE_ENABLED', 'Enable Mode Brake', 0, None),
     Feature('Copter', 'COPTER_ADVANCED_FAILSAFE', 'AP_COPTER_ADVANCED_FAILSAFE_ENABLED', 'Enable Advanced Failsafe', 0, "ADVANCED_FAILSAFE"),  # NOQA: 501
+    Feature('Copter', 'COPTER_AHRS_AUTO_TRIM', 'AP_COPTER_AHRS_AUTO_TRIM_ENABLED', 'Enable Copter in-flight AHRS Trim calibration', 0, None),  # noqa
 
     Feature('Rover', 'ROVER_ADVANCED_FAILSAFE', 'AP_ROVER_ADVANCED_FAILSAFE_ENABLED', 'Enable Advanced Failsafe', 0, "ADVANCED_FAILSAFE"),  # NOQA: 501
 
diff --git a/Tools/scripts/extract_features.py b/Tools/scripts/extract_features.py
index 76be68dd361ef..6d2b79aeef747 100755
--- a/Tools/scripts/extract_features.py
+++ b/Tools/scripts/extract_features.py
@@ -278,6 +278,7 @@ def __init__(self, filename, nm="arm-none-eabi-nm", strings="strings"):
 
             ('AP_ROVER_ADVANCED_FAILSAFE_ENABLED', r'Rover::afs_fs_check'),
             ('AP_COPTER_ADVANCED_FAILSAFE_ENABLED', r'Copter::afs_fs_check'),
+            ('AP_COPTER_AHRS_AUTO_TRIM_ENABLED', r'RC_Channels_Copter::auto_trim_run'),
 
             ('AP_PLANE_OFFBOARD_GUIDED_SLEW_ENABLED', r'GCS_MAVLINK_Plane::handle_command_int_guided_slew_commands'),
             ('AP_SERIALMANAGER_REGISTER_ENABLED', r'AP_SerialManager::register_port'),
diff --git a/libraries/AP_Mount/AP_Mount_Viewpro.cpp b/libraries/AP_Mount/AP_Mount_Viewpro.cpp
index aa443483e82b2..73cc963645ce5 100644
--- a/libraries/AP_Mount/AP_Mount_Viewpro.cpp
+++ b/libraries/AP_Mount/AP_Mount_Viewpro.cpp
@@ -20,7 +20,8 @@ extern const AP_HAL::HAL& hal;
 #define AP_MOUNT_VIEWPRO_DATALEN_MAX   (AP_MOUNT_VIEWPRO_PACKETLEN_MAX-AP_MOUNT_VIEWPRO_PACKETLEN_MIN) // max bytes for data portion of packet
 #define AP_MOUNT_VIEWPRO_HEALTH_TIMEOUT_MS 1000 // state will become unhealthy if no attitude is received within this timeout
 #define AP_MOUNT_VIEWPRO_UPDATE_INTERVAL_MS 100 // resend angle or rate targets to gimbal at this interval
-#define AP_MOUNT_VIEWPRO_ZOOM_SPEED     0x07    // hard-coded zoom speed (fast)
+#define AP_MOUNT_VIEWPRO_EO_ZOOM_SPEED     0x07    // hard-coded zoom speed (fast)
+#define AP_MOUNT_VIEWPRO_IR_ZOOM_SPEED     1 
 #define AP_MOUNT_VIEWPRO_ZOOM_MAX       10      // hard-coded absolute zoom times max
 #define AP_MOUNT_VIEWPRO_DEG_TO_OUTPUT  (65536.0 / 360.0)   // scalar to convert degrees to the viewpro angle scaling
 #define AP_MOUNT_VIEWPRO_OUTPUT_TO_DEG  (360.0 / 65536.0)   // scalar to convert viewpro angle scaling to degrees
@@ -349,9 +350,19 @@ void AP_Mount_Viewpro::process_packet()
             GCS_SEND_TEXT(MAV_SEVERITY_INFO,  "%s recording %s", send_text_prefix, _recording ? "ON" : "OFF");
         }
 
-        // get optical zoom times
-        _zoom_times = UINT16_VALUE(_msg_buff[_msg_buff_data_start+39], _msg_buff[_msg_buff_data_start+40]) * 0.1;
-
+        switch (_image_sensor) {
+            default:   
+            case ImageSensor::EO1:
+            case ImageSensor::EO1_IR_PIP:
+                //optical zoom times
+                _zoom_times = UINT16_VALUE(_msg_buff[_msg_buff_data_start+39], _msg_buff[_msg_buff_data_start+40]) * 0.1;
+                break;
+            case ImageSensor::IR:
+            case ImageSensor::IR_EO1_PIP:
+                //ir zoom times
+                _zoom_times = ((_msg_buff[_msg_buff_data_start+29] >> 3) & 0x0F) + 1;
+                break;
+        }        
         // get laser rangefinder distance
         _rangefinder_dist_m = UINT16_VALUE(_msg_buff[_msg_buff_data_start+33], _msg_buff[_msg_buff_data_start+34]) * 0.1;
         break;
@@ -737,13 +748,32 @@ bool AP_Mount_Viewpro::set_zoom(ZoomType zoom_type, float zoom_value)
 
     // zoom rate
     if (zoom_type == ZoomType::RATE) {
+        uint8_t zoom_speed = 1;
         CameraCommand zoom_cmd = CameraCommand::STOP_FOCUS_AND_ZOOM;
-        if (zoom_value < 0) {
-            zoom_cmd = CameraCommand::ZOOM_OUT;
-        } else if (zoom_value > 0) {
-            zoom_cmd = CameraCommand::ZOOM_IN;
+        
+        switch (_image_sensor) {
+            default:   
+            case ImageSensor::EO1:
+            case ImageSensor::EO1_IR_PIP:
+                if (zoom_value < 0) {
+                    zoom_cmd = CameraCommand::ZOOM_OUT;
+                } else if (zoom_value > 0) {
+                    zoom_cmd = CameraCommand::ZOOM_IN;
+                }
+                zoom_speed = AP_MOUNT_VIEWPRO_EO_ZOOM_SPEED;
+                break;
+            case ImageSensor::IR:
+            case ImageSensor::IR_EO1_PIP:
+                if (zoom_value < 0) {
+                    zoom_cmd = CameraCommand::IR_ZOOM_IN;
+                } else if (zoom_value > 0) {
+                    zoom_cmd = CameraCommand::IR_ZOOM_OUT;
+                }
+                zoom_speed = AP_MOUNT_VIEWPRO_IR_ZOOM_SPEED;
+                break;    
         }
-        return send_camera_command(_image_sensor, zoom_cmd, AP_MOUNT_VIEWPRO_ZOOM_SPEED);
+        
+        return send_camera_command(_image_sensor, zoom_cmd, zoom_speed);
     }
 
     // zoom percentage
diff --git a/libraries/AP_Mount/AP_Mount_Viewpro.h b/libraries/AP_Mount/AP_Mount_Viewpro.h
index 1100586cd1ce1..214394a32416a 100644
--- a/libraries/AP_Mount/AP_Mount_Viewpro.h
+++ b/libraries/AP_Mount/AP_Mount_Viewpro.h
@@ -160,7 +160,9 @@ class AP_Mount_Viewpro : public AP_Mount_Backend_Serial
         START_RECORD = 0x14,
         STOP_RECORD = 0x15,
         AUTO_FOCUS = 0x19,
-        MANUAL_FOCUS = 0x1A
+        MANUAL_FOCUS = 0x1A,
+        IR_ZOOM_OUT = 0x1B,
+        IR_ZOOM_IN = 0x1C
     };
 
     // C1 rangefinder commands
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol.cpp b/libraries/GCS_MAVLink/MissionItemProtocol.cpp
index c7af789559e34..9e92377e0bb9c 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol.cpp
+++ b/libraries/GCS_MAVLink/MissionItemProtocol.cpp
@@ -155,9 +155,19 @@ void MissionItemProtocol::handle_mission_request_int(GCS_MAVLINK &_link,
     }
 
     mavlink_mission_item_int_t ret_packet;
-    const MAV_MISSION_RESULT result_code = get_item(_link, msg, packet, ret_packet);
-
+    const MAV_MISSION_RESULT result_code = get_item(packet.seq, ret_packet);
     if (result_code != MAV_MISSION_ACCEPTED) {
+        if (result_code == MAV_MISSION_INVALID_SEQUENCE) {
+            // try to educate the GCS on the actual size of the mission:
+            const mavlink_channel_t chan = _link.get_chan();
+            if (HAVE_PAYLOAD_SPACE(chan, MISSION_COUNT)) {
+                mavlink_msg_mission_count_send(chan,
+                                               msg.sysid,
+                                               msg.compid,
+                                               item_count(),
+                                               mission_type());
+            }
+        }
         // send failure message
         send_mission_ack(_link, msg, result_code);
         return;
@@ -179,15 +189,8 @@ void MissionItemProtocol::handle_mission_request(GCS_MAVLINK &_link,
         return;
     }
 
-    // convert into a MISSION_REQUEST_INT and reuse its handling code
-    mavlink_mission_request_int_t request_int;
-    request_int.target_system = packet.target_system;
-    request_int.target_component = packet.target_component;
-    request_int.seq = packet.seq;
-    request_int.mission_type = packet.mission_type;
-
     mavlink_mission_item_int_t item_int;
-    MAV_MISSION_RESULT ret = get_item(_link, msg, request_int, item_int);
+    MAV_MISSION_RESULT ret = get_item(packet.seq, item_int);
     if (ret != MAV_MISSION_ACCEPTED) {
         send_mission_ack(_link, msg, ret);
         return;
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol.h b/libraries/GCS_MAVLink/MissionItemProtocol.h
index 37f37fd559716..ff8a6ae73adbf 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol.h
+++ b/libraries/GCS_MAVLink/MissionItemProtocol.h
@@ -102,9 +102,7 @@ class MissionItemProtocol
     bool mission_item_warning_sent = false;
 
     // support for GCS getting waypoints etc from us:
-    virtual MAV_MISSION_RESULT get_item(const GCS_MAVLINK &_link,
-                                        const mavlink_message_t &msg,
-                                        const mavlink_mission_request_int_t &packet,
+    virtual MAV_MISSION_RESULT get_item(uint16_t seq,
                                         mavlink_mission_item_int_t &ret_packet) = 0;
 
     void init_send_requests(GCS_MAVLINK &_link,
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol_Fence.cpp b/libraries/GCS_MAVLink/MissionItemProtocol_Fence.cpp
index c50001cc12dd7..df945641c4d21 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol_Fence.cpp
+++ b/libraries/GCS_MAVLink/MissionItemProtocol_Fence.cpp
@@ -74,17 +74,13 @@ bool MissionItemProtocol_Fence::get_item_as_mission_item(uint16_t seq,
     return true;
 }
 
-MAV_MISSION_RESULT MissionItemProtocol_Fence::get_item(const GCS_MAVLINK &_link,
-                                                       const mavlink_message_t &msg,
-                                                       const mavlink_mission_request_int_t &packet,
-                                                       mavlink_mission_item_int_t &ret_packet)
+MAV_MISSION_RESULT MissionItemProtocol_Fence::get_item(uint16_t seq, mavlink_mission_item_int_t &ret_packet)
 {
-    const auto num_stored_items = _fence.polyfence().num_stored_items();
-    if (packet.seq > num_stored_items) {
+    if (seq >= _fence.polyfence().num_stored_items()) {
         return MAV_MISSION_INVALID_SEQUENCE;
     }
 
-    if (!get_item_as_mission_item(packet.seq, ret_packet)) {
+    if (!get_item_as_mission_item(seq, ret_packet)) {
         return MAV_MISSION_ERROR;
     }
 
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol_Fence.h b/libraries/GCS_MAVLink/MissionItemProtocol_Fence.h
index 58a984f60a821..e724891a6622e 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol_Fence.h
+++ b/libraries/GCS_MAVLink/MissionItemProtocol_Fence.h
@@ -42,10 +42,7 @@ class MissionItemProtocol_Fence : public MissionItemProtocol {
     MAV_MISSION_RESULT replace_item(const mavlink_mission_item_int_t&) override WARN_IF_UNUSED;
     MAV_MISSION_RESULT append_item(const mavlink_mission_item_int_t&) override WARN_IF_UNUSED;
 
-    MAV_MISSION_RESULT get_item(const GCS_MAVLINK &_link,
-                                const mavlink_message_t &msg,
-                                const mavlink_mission_request_int_t &packet,
-                                mavlink_mission_item_int_t &ret_packet) override WARN_IF_UNUSED;
+    MAV_MISSION_RESULT get_item(uint16_t seq, mavlink_mission_item_int_t &ret_packet) override WARN_IF_UNUSED;
 
     void free_upload_resources() override;
     MAV_MISSION_RESULT allocate_receive_resources(const uint16_t count) override WARN_IF_UNUSED;
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol_Rally.cpp b/libraries/GCS_MAVLink/MissionItemProtocol_Rally.cpp
index 0af495d7ff81a..ad330039c33f9 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol_Rally.cpp
+++ b/libraries/GCS_MAVLink/MissionItemProtocol_Rally.cpp
@@ -150,12 +150,13 @@ bool MissionItemProtocol_Rally::get_item_as_mission_item(uint16_t seq,
     return true;
 }
 
-MAV_MISSION_RESULT MissionItemProtocol_Rally::get_item(const GCS_MAVLINK &_link,
-                                                       const mavlink_message_t &msg,
-                                                       const mavlink_mission_request_int_t &packet,
-                                                       mavlink_mission_item_int_t &ret_packet)
+MAV_MISSION_RESULT MissionItemProtocol_Rally::get_item(uint16_t seq, mavlink_mission_item_int_t &ret_packet)
 {
-    if (!get_item_as_mission_item(packet.seq, ret_packet)) {
+    if (seq >= item_count()) {
+        return MAV_MISSION_INVALID_SEQUENCE;
+    }
+
+    if (!get_item_as_mission_item(seq, ret_packet)) {
         return MAV_MISSION_INVALID_SEQUENCE;
     }
     return MAV_MISSION_ACCEPTED;
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol_Rally.h b/libraries/GCS_MAVLink/MissionItemProtocol_Rally.h
index add6efa6ca53e..b2aaf1ff03af2 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol_Rally.h
+++ b/libraries/GCS_MAVLink/MissionItemProtocol_Rally.h
@@ -39,10 +39,7 @@ class MissionItemProtocol_Rally : public MissionItemProtocol {
     MAV_MISSION_RESULT replace_item(const mavlink_mission_item_int_t&) override WARN_IF_UNUSED;
     MAV_MISSION_RESULT append_item(const mavlink_mission_item_int_t&) override WARN_IF_UNUSED;
 
-    MAV_MISSION_RESULT get_item(const GCS_MAVLINK &_link,
-                                const mavlink_message_t &msg,
-                                const mavlink_mission_request_int_t &packet,
-                                mavlink_mission_item_int_t &ret_packet) override WARN_IF_UNUSED;
+    MAV_MISSION_RESULT get_item(uint16_t seq, mavlink_mission_item_int_t &ret_packet) override WARN_IF_UNUSED;
 
 };
 
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.cpp b/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.cpp
index 7ce5787d46459..a1987c457cd12 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.cpp
+++ b/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.cpp
@@ -64,29 +64,17 @@ MAV_MISSION_RESULT MissionItemProtocol_Waypoints::complete(const GCS_MAVLINK &_l
     return MAV_MISSION_ACCEPTED;
 }
 
-MAV_MISSION_RESULT MissionItemProtocol_Waypoints::get_item(const GCS_MAVLINK &_link,
-                                                           const mavlink_message_t &msg,
-                                                           const mavlink_mission_request_int_t &packet,
-                                                           mavlink_mission_item_int_t &ret_packet)
+MAV_MISSION_RESULT MissionItemProtocol_Waypoints::get_item(uint16_t seq, mavlink_mission_item_int_t &ret_packet)
 {
-    if (packet.seq != 0 && // always allow HOME to be read
-        packet.seq >= mission.num_commands()) {
-        // try to educate the GCS on the actual size of the mission:
-        const mavlink_channel_t chan = _link.get_chan();
-        if (HAVE_PAYLOAD_SPACE(chan, MISSION_COUNT)) {
-            mavlink_msg_mission_count_send(chan,
-                                           msg.sysid,
-                                           msg.compid,
-                                           mission.num_commands(),
-                                           MAV_MISSION_TYPE_MISSION);
-        }
-        return MAV_MISSION_ERROR;
+    if (seq != 0 && // always allow HOME to be read
+        seq >= mission.num_commands()) {
+        return MAV_MISSION_INVALID_SEQUENCE;
     }
 
     AP_Mission::Mission_Command cmd;
 
     // retrieve mission from eeprom
-    if (!mission.read_cmd_from_storage(packet.seq, cmd)) {
+    if (!mission.read_cmd_from_storage(seq, cmd)) {
         return MAV_MISSION_ERROR;
     }
 
diff --git a/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.h b/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.h
index 5a7ee4e86ea36..b5592b776447d 100644
--- a/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.h
+++ b/libraries/GCS_MAVLink/MissionItemProtocol_Waypoints.h
@@ -45,14 +45,8 @@ class MissionItemProtocol_Waypoints : public MissionItemProtocol {
     // item to the end of the list of stored items.
     MAV_MISSION_RESULT append_item(const mavlink_mission_item_int_t &) override WARN_IF_UNUSED;
 
-    // get_item() fills in ret_packet based on packet; _link is the
-    // link the request was received on, and msg is the undecoded
-    // request.  Note that msg may not actually decode to a
-    // request_int_t!
-    MAV_MISSION_RESULT get_item(const GCS_MAVLINK &_link,
-                                const mavlink_message_t &msg,
-                                const mavlink_mission_request_int_t &packet,
-                                mavlink_mission_item_int_t &ret_packet) override WARN_IF_UNUSED;
+    // support for GCS getting waypoints etc from us:
+    MAV_MISSION_RESULT get_item(uint16_t seq, mavlink_mission_item_int_t &ret_packet) override WARN_IF_UNUSED;
 
     // item_count() returns the number of stored items
     uint16_t item_count() const override;
diff --git a/libraries/RC_Channel/RC_Channel.h b/libraries/RC_Channel/RC_Channel.h
index 6bd477cdaf185..0e1fe150c7b69 100644
--- a/libraries/RC_Channel/RC_Channel.h
+++ b/libraries/RC_Channel/RC_Channel.h
@@ -261,7 +261,7 @@ class RC_Channel {
         ICE_START_STOP =     179, // AP_ICEngine start stop
         AUTOTUNE_TEST_GAINS = 180, // auto tune tuning switch to test or revert gains
         QUICKTUNE =          181,  //quicktune 3 position switch
-
+        AHRS_AUTO_TRIM =     182,  // in-flight trim Copter AHRS using manual levelling
 
         // inputs from 200 will eventually used to replace RCMAP
         ROLL =               201, // roll input