accounts: add warning regarding saml plugin usage

Signed-off-by: Rohit Yadav <rohit@scaleninja.com>
diff --git a/source/accounts.rst b/source/accounts.rst
index 9c89212..63a2337 100644
--- a/source/accounts.rst
+++ b/source/accounts.rst
@@ -272,6 +272,10 @@
 Using a SAML 2.0 Identity Provider for User Authentication
 ----------------------------------------------------------
 
+NOTE: The SAML2 auth plugin introduced in Apache CloudStack 4.5,
+should be considered experimental and has not been tested in production, therefore
+may change in future breaking implementation and semantics compatibility.
+
 You can use a SAML 2.0 Identity Provider with CloudStack for user
 authentication. This will require enabling the SAML 2.0 service provider plugin
 in CloudStack. On successful authentication, CloudStack will use the persistent