diff --git a/Gemfile.lock b/Gemfile.lock
index 9476f65e..5963536d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -132,7 +132,7 @@ GEM
     mini_mime (1.1.5)
     mini_portile2 (2.8.5)
     minitest (5.22.2)
-    mysql2 (0.5.5)
+    mysql2 (0.5.6)
     net-imap (0.3.4)
       date
       net-protocol