diff --git a/Gemfile.lock b/Gemfile.lock
index 12e357b..3eb5524 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -5,6 +5,7 @@ GEM
       public_suffix (~> 2.0, >= 2.0.2)
     backports (3.15.0)
     base32 (0.3.2)
+    concurrent-ruby (1.1.10)
     connection_pool (2.2.3)
     daemons (1.2.4)
     dalli (2.7.6)
@@ -127,14 +128,13 @@ GEM
       daemons (~> 1.0, >= 1.0.9)
       eventmachine (~> 1.0, >= 1.0.4)
       rack (>= 1, < 3)
-    thread_safe (0.3.6)
     tilt (2.0.10)
     twilio-ruby (5.1.1)
       faraday (~> 0.9)
       jwt (~> 1.5)
       libxml-ruby (= 3.0.0)
-    tzinfo (1.2.3)
-      thread_safe (~> 0.1)
+    tzinfo (2.0.5)
+      concurrent-ruby (~> 1.0)
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.7)