v1.3.1

### Releases v1.3.1

1. Clean-up all compiler warnings possible.
2. Add Table of Contents

Author: khoih-prog

README.md

@@ -344,7 +344,7 @@ This file must be copied into the directory:
 
  ***To be able to compile without error and automatically detect and display BOARD_NAME on Arduino SAMD (Nano-33-IoT, etc) boards***, you have to copy the whole [Arduino SAMD cores 1.8.10](Packages_Patches/arduino/hardware/samd/1.8.10) directory into Arduino SAMD directory (~/.arduino15/packages/arduino/hardware/samd/1.8.10).
 
-#### For core version v1.8.11+
+#### For core version v1.8.10+
 
 Supposing the Arduino SAMD version is 1.8.11. Now only one file must be copied into the directory: