diff --git a/contrib/byteify-strings.py b/contrib/byteify-strings.py
--- a/contrib/byteify-strings.py
+++ b/contrib/byteify-strings.py
@@ -339,7 +339,7 @@ def main():
 
 
 if __name__ == '__main__':
-    if sys.version_info.major < 3:
-        print('This script must be run under Python 3.')
+    if sys.version_info[0:2] < (3, 6):
+        print('This script must be run under Python 3.6+')
         sys.exit(3)
     main()
diff --git a/tests/test-byteify-strings.t b/tests/test-byteify-strings.t
--- a/tests/test-byteify-strings.t
+++ b/tests/test-byteify-strings.t
@@ -1,4 +1,4 @@
-#require py3
+#require py36
 
   $ byteify_strings () {
   >   $PYTHON "$TESTDIR/../contrib/byteify-strings.py" "$@"