diff --git a/ArduCopter/ReleaseNotes.txt b/ArduCopter/ReleaseNotes.txt
index e1ba054a89..b8e04a380e 100644
--- a/ArduCopter/ReleaseNotes.txt
+++ b/ArduCopter/ReleaseNotes.txt
@@ -1,5 +1,127 @@
 ArduPilot Copter Release Notes:
 ------------------------------------------------------------------
+Copter 4.2.0-rc1 28-Feb-2022
+Changes from 4.1.5
+1) AHRS/EKF improvements
+    a) EKF startup messages reduced
+    b) GPS<->Opticalflow automatic switching improved (see ahrs-source-gps-optflow.lua script)
+    c) LORD Microstrain CX5/GX5 external AHRS support
+    d) ModalAI VOXL non-GPS system supported (set VISO_TYPE=3, uses ODOMETRY mavlink msg)
+2) Control and flight mode enhancements
+    a) Acro max rate params renamed and improved (see ACRO_RP_RATE, ACRO_Y_RATE, PILOT_Y_RATE, PILOT_Y_EXPO)
+    b) Airmode NOT enabled when arming with switch (see ACRO_OPTIONS and "ArmDisarm with AirMode" RCx_OPTION)
+    c) Auto and Guided support pausing (uses DO_PAUSE_CONTINUE mavlink command)
+    d) Auto supports up to 100 DO_JUMP commands on high memory boards
+    e) Autotune reporting improved (less spam, prints final tune)
+    f) FLIGHT_OPTIONS to release gripper on thrust loss
+    g) ForceFlying auxiliary switch allows pilot to disable land-detector
+    h) Guided mode acceleration target support
+    i) Guided mode logging of targets improved (GUID msg split into GUIP, GUIA)
+    j) Harmonic notch filter on more than four motors
+    k) Land mode pilot controlled repositioning max speed reduced (also affects RTL and Auto)
+    l) Precision landing improvements esp when using PLAND_EST_TYPE = 1/KalmanFilter
+    m) RTL's safe altitude (RTL_ALT) increased 85km (was 325m)
+    n) Simple mode heading reset via auxiliary switch
+    o) Sport mode deprecated
+    p) SURFTRAK_MODE allows disabling surface tracking in Loiter, AltHold, etc
+    q) Turtle mode (allows righting a copter while on the ground)
+3) Custom build server support (see https://custom.ardupilot.org)
+4) Lua scripting improvements
+    a) ahrs::get_location replaces get_position (get_position still works for now)
+    b) Auto support for NAV_SCRIPT_TIME commands (Lua within Auto)
+    c) Frame string support (allows scripting based frame to display custom description after startup)
+    d) Parameter support (no need to always use SCR_USERx)
+    e) Servo output control by channel number (previously was only possibly by specifying the SERVOn_FUNCTION value) 
+    f) Script logged to onboard log (can be disabled by setting SCR_DEBUG_OPTS)
+5) New autopilots supported
+    a) AirLink
+    b) BeastF7v2, BeastH7v2
+    c) JHEMCU GSF405A
+    d) KakuteH7, KakuteH7Mini
+    e) MambaF405US-I2C
+    f) MatekF405-TE
+    g) ModalAI fc-v1
+    h) PixC4-Jetson
+    i) Pixhawk5X
+    j) QioTekZealotH743
+    k) RPI-Zero2W
+    l) SPRacingH7 Extreme
+    m) Swan-K1
+6) Safety improvements
+    a) Dijkstra's avoidance performance improvements including converting to A*
+    b) Motor PWM range always uses MOT_PWM_MIN/MAX (if these are not set, they are defaulted to RC3_MIN/MAX values)
+    c) Parachute option to leave servo in open position (see CHUTE_OPTIONS parameter)
+    d) Parachute released arming check added
+    e) Pre-arm check of IMU heater temp
+    f) Pre-arm check of rangefinder health
+    g) Pre-arm check of throttle position skipped if PILOT_THR_BHV is "Feedback from mid stick"
+7) Sensor driver enhancements
+    a) ADIS16470, ADIS16507 and BMI270 IMU support
+    b) Airspeed sensor support (reporting only, not used for estimation or control)
+    c) AK09918 compass support
+    d) Battery monitor supports voltage offset (see BATTx_VLT_OFFSET)
+    e) Benewake TFMiniPlus I2C address defaults correctly
+    f) Buzzer can be connected to any GPIO on any board
+    g) Compass calibration (in-flight) uses GSF for better accuracy
+    h) CRSFv3 support, CSRF telemetry link reports link quality in RSSI
+    i) Cybot D1 Lidar
+    j) DroneCan (aka UAVCAN) battery monitors support scaling (see BATTx_CURR_MULT)
+    k) DroneCan (aka UAVCAN) GPS-for-yaw support
+    l) Electronic Fuel Injection support incl Lutan EFI
+    m) FETtecOneWire resyncs if EMI causes lost bytes
+    n) IMU heater params renamed to BRD_HEAT_xxx
+    o) Landing gear enable parameter added (see LGR_ENABLE)
+    p) Lightware SF40C ver 0.9 support removed (ver 1.0 and higher still supported)
+    q) Maxbotix serial sonar driver support RNGFNDx_SCALING parameter to support for varieties of sensor
+    r) MPPT solar charge controller support
+    s) MTK GPS driver removed
+    t) Optical flow in-flight calibration
+    u) Ping200x support
+    v) Proximity sensor min and max range (see PRX_MIN, PRX_MAX)
+    w) QSPI external flash support
+    x) uLanding (aka USD1) radar provides average of last few samples
+    y) Unicore NMEA GPS support for yaw and 3D velocity 
+8) TradHeli enhancements
+    a) Attitude control default gains improved
+        - ATC_RAT_RLL_FF, _I, _IMAX, _ILMI, _FLTT
+        - ATC_RAT_PIT_FF, _I, _IMAX, _ILMI, _FLTT
+        - ATC_RAT_YAW_IMAX, _FLTT
+    b) AutoTune mode
+    c) Collective setup  (users will be forced to setup new collective parameters)
+    d) Rotor Speed Controller Internal Governor improvements (users required to retune governor)
+    e) Rotor Speed Controller Cooldown timer added for ICE and turbine engines
+    f) _VFF params renamed to _FF
+9) Other System enhancements
+    a) Board ID sent in AUTOPILOT_VERSION mavlink message
+    b) Compass calibration stick gestures removed
+    c) DO_SET_CAM_TRIG_DIST supports instantly triggering camera
+    d) DJI FPV OSD multi screen and stats support
+    e) GPIO pins configured by setting SERVOx_FUNCTION to -1 (also see SERVO_GPIO_MASK. BRD_PWM_COUNT removed)
+    f) GPIO pin support on main outputs on boards with IOMCU
+    g) GyroFlow logging (see LOG_BITMASK's "VideoStabilization" option)
+    h) Firmware version logged in VER message
+    i) SD card format via MAVLink
+    j) Serial port option to disable changes to stream rate (see SERIALx_OPTIONS)
+    k) VIBE logging units to m/s/s
+10) Bug fixes
+    a) Auto and Guided mode takeoff alt fixed if taking off from below home or frame set to absolute (aka AMSL)
+    b) Auto mode CONDITION_YAW command completion fix
+    c) Auto mode infinite loop with nav commands that fail to start fixed
+    d) AutoTune disables ATC_RAT_xxx_SMAX during twitch (SMAX may limit gains to reduce oscillation) 
+    e) BLHeli passthrough reliability improvements
+    f) Compass learning (inflight) fixed to ignore unused compasses (e.g. those with COMPASS_USE = 0)
+    g) EKF optical flow terrain alt reset fixed (large changes in rangefinder alt might never be fused)
+    h) EKF resets due to bad IMU data occur at most once per second
+    i) GPIO pin fix on CubeOrange, F4BY, mRoControlZeroF7, R9Pilot
+    j) Guided mode yaw rate timeout fix (vehicle could keep yawing even if companion computer stopped sending target)
+    k) MAVlink2 serial ports always send MAVLink2 messages (previously waited until other side sent MAVLink2)
+    l) Motor Test, Turtle mode respect emergency stop switch
+    m) Omnibusf4pro bi-directional dshot fix
+    n) PosHold braking fix if SCHED_LOOP_RATE set to non-default value
+    o) Precision landing in RTL activates even if pilot had earlier deactivated by repositioning in Land
+    p) Real-Time-Clock (RTC) oldest possible date updated to Jan-2022
+    q) Tricopter, Coax copter fin trim fix when using DShot/BLheli
+------------------------------------------------------------------
 Copter 4.1.5 19-Feb-2022 / 4.1.5-rc1 10-Feb-2022
 Changes from 4.1.4
 1) Bug fixes