diff --git a/Gemfile.lock b/Gemfile.lock
index fbe07a9..924958d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -70,7 +70,7 @@ GEM
       railties (>= 3.0, < 5.0)
       thor (>= 0.14, < 2.0)
     json (1.8.3)
-    mail (2.5.4)
+    mail (2.5.5)
       mime-types (~> 1.16)
       treetop (~> 1.4.8)
     mime-types (1.25.1)