diff --git a/python-rt.spec b/python-rt.spec
index 3c32c2a..0ef8d82 100644
--- a/python-rt.spec
+++ b/python-rt.spec
@@ -25,6 +25,7 @@ Group:          Development/Languages/Python
 URL:            https://github.com/CZ-NIC/python-rt
 Source:         https://files.pythonhosted.org/packages/source/r/rt/rt-%{version}.tar.gz
 Source1:        setup.cfg
+BuildRequires:  %{python_module base >= 3.7}
 BuildRequires:  %{python_module pip}
 BuildRequires:  %{python_module setuptools}
 BuildRequires:  %{python_module wheel}