diff --git a/etc/tempest.conf.sample b/etc/tempest.conf.sample
index 48ca905..fb11d96 100644
--- a/etc/tempest.conf.sample
+++ b/etc/tempest.conf.sample
@@ -397,6 +397,11 @@
 # (string value)
 #uri_v3=<None>
 
+# Identity API version to be used for authentication for API
+# tests. Planned to extend to tenant isolation, scenario tests
+# and CLI tests. (string value)
+#auth_version=v2
+
 # The identity region name to use. Also used as the other
 # services' region name unless they are set explicitly. If no
 # such region is found in the service catalog, the first found