diff --git a/mail/Gemfile.lock b/mail/Gemfile.lock
index 7030b77..fb49176 100644
--- a/mail/Gemfile.lock
+++ b/mail/Gemfile.lock
@@ -2,7 +2,7 @@ GEM
   remote: https://rubygems.org/
   specs:
     highline (1.7.8)
-    json (1.8.3)
+    json (2.6.3)
     mail (2.6.4)
       mime-types (>= 1.16, < 4)
     mime-types (3.1)