diff --git a/dkimverify.py b/dkimverify.py
index 1e8be81..3294c74 100644
--- a/dkimverify.py
+++ b/dkimverify.py
@@ -27,7 +27,7 @@ import sys
 
 import dkim
 
-if sys.version_info.major >= 3:
+if sys.version_info[0] >= 3:
     # Make sys.stdin a binary stream.
     sys.stdin = sys.stdin.detach()