Updated Installation (markdown)

Installation.md

@@ -3,6 +3,7 @@
 Prerequisites:
 - Requires Ubuntu 14.04+ OR a working Docker installation. See [Docker Installation](Docker.md) for instructions installing using Docker.
 - Minimum 4GB of RAM, recommended 16GB or more. 
+- Currently ODM only is supported up to Ubuntu 16.04 due to some package going obsolete. We're working on it. 
 
 Install Git tools