diff --git a/Gemfile.lock b/Gemfile.lock
index a82507eb..718ae41d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -143,7 +143,7 @@ GEM
     mini_portile2 (2.8.4)
     minitest (5.20.0)
     msgpack (1.7.2)
-    net-imap (0.3.7)
+    net-imap (0.4.0)
       date
       net-protocol
     net-pop (0.1.2)