diff --git a/Gemfile b/Gemfile
index c0dbdb3bdeb..e03c16df6df 100644
--- a/Gemfile
+++ b/Gemfile
@@ -59,7 +59,7 @@ gem 'typed_dag', '~> 2.0.2'
 gem 'addressable', '~> 2.5.2'
 
 # Provide timezone info for TZInfo used by AR
-gem 'tzinfo-data', '~> 1.2018.4'
+gem 'tzinfo-data', '~> 1.2018.9'
 
 # to generate html-diffs (e.g. for wiki comparison)
 gem 'htmldiff'
diff --git a/Gemfile.lock b/Gemfile.lock
index 06d86a71cd4..47237f4a419 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -798,7 +798,7 @@ GEM
       rails (>= 5.0.4)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
-    tzinfo-data (1.2018.4)
+    tzinfo-data (1.2018.9)
       tzinfo (>= 1.0.0)
     uber (0.1.0)
     unf (0.1.4)
@@ -988,7 +988,7 @@ DEPENDENCIES
   timecop (~> 0.9.0)
   transactional_lock!
   typed_dag (~> 2.0.2)
-  tzinfo-data (~> 1.2018.4)
+  tzinfo-data (~> 1.2018.9)
   unicorn
   unicorn-worker-killer
   warden (~> 1.2)