Add remarks regarding WiFi password limits

Author: tomikaa87

README.md

@@ -525,10 +525,12 @@ And the device will send a response like that:
 }
 ```
 
-### Remarks
+## Remarks
 
 For the sake of simplicity, you can send device control messages to the broadcast address instead of the IP of the device, because the `tcid` field addresses the device properly. With this little trick you can omit storing IP addresses for specific devices.
 
+Different units have different firmware versions. Some of them have weird limitations. One of these can be a WiFi password length limitation. WPA supports 63-character long passwords, but some units limit this to 31 characters. Please be aware of this issue when your units can't connect to your network.
+
 ### The units talk home to China, what can I do?
 
 The WiFi controller in these devices has the ability to be controlled through the cloud. To be able to do that, they periodically send "heartbeat" packets to Gree servers which are located in China.