Use old style string formatting to appease readthedocs aging 3.5 interpreter.
@@ -10,7 +10,7 @@ from pyinfra import __version__
_today = date.today()
-copyright = f'{datetime.strftime(_today, "%Y")}, Nick Barrett'
+copyright = '{0}, Nick Barrett'.format(datetime.strftime(_today, '%Y'))
extensions = [
# Official
