diff --git a/tests/common/test_transaction.py b/tests/common/test_transaction.py
index 6bf1b44e..294c72dc 100644
--- a/tests/common/test_transaction.py
+++ b/tests/common/test_transaction.py
@@ -974,6 +974,7 @@ def test_validate_version(utx):
 
     validate_transaction_model(utx)
 
+    # At version 1, transaction version will break step with server version.
     utx.version = '1.0.0'
     with raises(SchemaValidationError):
         validate_transaction_model(utx)