diff --git a/README.md b/README.md
index 2c7c003..55f2805 100644
--- a/README.md
+++ b/README.md
@@ -65,6 +65,7 @@ versions:
 
 * Ruby 2.2.6+
 * Ruby 2.3.0+
+* Ruby 2.4.2+
 * JRuby 9.1.6.0+
 
 If something doesn't work on one of these versions, it's a bug.