diff --git a/README.md b/README.md
index a9e2012..df83ddc 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,6 @@
 # bash-ssl-checker-tool
 This is a very simple bash script that you could use to gain general information for the SSL certificate of a certain domain name. It is based on the functionality of the popular https://sslshopper.com website, but it's a command line tool.
-The script has been tested on CentOS, Ubuntu, Mint and Debian
+
+The script has been tested on CentOS, Ubuntu, Mint and Debian.
+
+Note: You need to have 'openssl' installed.