diff --git a/ArduCopter/ReleaseNotes.txt b/ArduCopter/ReleaseNotes.txt
index 6792002663..8b40b401fd 100644
--- a/ArduCopter/ReleaseNotes.txt
+++ b/ArduCopter/ReleaseNotes.txt
@@ -1,5 +1,28 @@
 APM:Copter Release Notes:
 ------------------------------------------------------------------
+Copter 3.4.0-rc1 28-May-2016
+Changes from 3.3.3
+1) EKF2 allows "boat mode" (attitude initialisation without gyro calibration)
+2) Throw mode
+3) Terrain following:
+    a) support terrain altitudes during missions using GCS's map data or rangefinder (i.e. Lidar)
+    b) LightWare range finder driver fixes (I2C works)
+    c) Bebop sonar support
+4) Precision Landing using IRLock sensor
+5) Attitude controller re-organisation (all parameter changes automatically moved and scales adjusted)
+    a) RATE_ parameters become ATC_RAT_ (i.e. RATE_RLL_P becomes ATC_RAT_RLL_P) 
+    b) Rate Roll, Pitch, Yaw P, D are reduced by 10% for X, V, H frames, increased by 27% for all other frames
+    c) STB_ parameters becomes ATC_ANG_ (i.e. STB_RLL_P becomes ATC_ANG_RLL_P)
+6) Motors library improvements:
+    a) support OneShot ESCs (set MOT_PWM_TYPE to 0 for Normal, 1 for OneShot or 2 for OneShot125)
+    b) TriCopter compensates for tail servo angle
+    c) SingleCopter, CoaxCopter adjust control surfaces based on throttle output
+    d) MOT_PWM_MIN, MAX allow specifying output ranges to ESCs which are difference from throttle input channel (i.e. RC3)
+    e) TradHeli servo objects moved into heli class (HSV_ parameters become H_SV_)
+7) uAvionix Ping sensor support (ADS-B vehicles appear on GCS, avoidance will come in future release) 
+8) Safety:
+    a) warning if GPS update rate is slow (under 5hz, does not stop arming) 
+------------------------------------------------------------------
 Copter 3.3.3 24-Feb-2016 / 3.3.3-rc2 27-Jan-2016
 Changes from 3.3.3-rc1
 1) bug fix to Guided mode's velocity controller to run at 400hz