diff --git a/README.md b/README.md
index d10d3c4..6494395 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 Command-line client for PaloAlto Networks' GlobalProtect VPN, integrated with OKTA.
 This utility will do the _authentication dance_ with OKTA to retrieve `portal-userauthcookie`,
 which will be passed to [OpenConnect with PAN GlobalProtect support](https://github.com/dlenski/openconnect)
-for creating actual VPN connection.
+for creating actual VPN connection. Tested on FreeBSD, Linux and MacOS X.
 
 It also supports Google and OKTA two factor authentication and can work without
 user interaction, if initial TOTP secret is provided. Otherwise, it will ask for