Added requirements for Python version

Signed-off-by: Ognian Baruh <fixed-term.Ognyan.Baruh@bosch.io>

Author: Ognian Baruh

README.md

@@ -18,12 +18,14 @@ This repository contains the Python client SDK for [Eclipse Ditto](https://eclip
 
 ## Installation
 
-Install the sources and execute the following command:
+Download the sources and execute the following command:
 
 ```commandline
 make install
 ```
 
+**_NOTE:_** Python >=3.6 is required in order to use the library.
+
 ## Creating and connecting a client
 
 It is a good practice to have a defined behaviour after connecting or disconnecting the client.