Update readme.md file for 4.3.1 release.

Author: mluis1

readme.md

@@ -23,14 +23,6 @@ In case only point to point links are required a Ping-Pong application is provid
 
 **Note 1:**
 
-*A version 3.x API to version 4.x API wrapper is available.
-Applications built using version 3.x API should work without modifications except that
-one must include LoRaMac-api-v3.h instead of LoRaMac.h file*
-
-**_The 3.x API wrapper will be deprecated starting at version 5.0.0_**
-
-**Note 2:**
-
 *A port of this project can be found on [MBED Semtech Team page](http://developer.mbed.org/teams/Semtech/)*
 
 *The example projects are:*
@@ -102,7 +94,7 @@ platforms are:
         BUTTONS : No
         LEDS    : 4
         SENSORS : Magnetic, 3 axis Accelerometer, Pressure,
-                    Temperature
+                  Temperature
         GPS     : Yes, SIM39EA module
         Display : OLED
         ST-Link : Yes, MBED like
@@ -150,6 +142,27 @@ not of a bootloader and the radio frequency band to be used.
 
 6. Changelog
 -------------
+2017-02-27, V4.3.1
+* General
+    1. This version has passed EU868 and US915 LoRa-Alliance compliance tests.
+    2. Update the MAC layer in order to be LoRaWAN version 1.0.1 compliant (Mainly US915 bug fixes)
+    3. Removed api-v3 support from the project.
+    4. GitHub reported issues corrections.
+    5. Updated SensorNode projects according to the new MCU reference STM32L151CBU6. Bigger memories.
+    6. Addition of MoteII platform based on the IMST module iM881A (STM32L051C8)
+    7. Addition of NAMote72 platform
+    8. Correct compliance test protocol command 0x06 behaviour
+    9. Added TxCw (Tx continuous wave) LoRaWAN compliance protocol command.
+    10. Added TxContinuousWave support to the radio drivers.
+    11. Updated ST HAL drivers.
+        - STM32L1xx_HAL-Driver : V1.2.0
+        - STM32L0xx_HAL_Driver : V1.7.0
+
+* LoRaWAN
+    1. US band corrections in order to pass the LoRaWAN certification.
+    2. GitHub reported issues corrections.
+    3. Add region CN470 support.
+
 2016-06-22, V4.3.0
 * General
     1. This version has passed all LoRa-Alliance compliance tests.