diff --git a/Gemfile b/Gemfile
index 67b88d49..e0e432f0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,7 @@ gem 'sinatra-flash',      require: 'sinatra/flash'
 gem 'sinatra-xsendfile',  require: 'sinatra/xsendfile'
 gem 'puma',               require: nil
 gem 'rmagick',            require: nil
-gem 'sidekiq', '~> 4.2.10'
+gem 'sidekiq', '~> 5.2.0'
 gem 'mail'
 gem 'tilt'
 gem 'erubis'
diff --git a/Gemfile.lock b/Gemfile.lock
index 7161634c..d074db31 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -44,8 +44,8 @@ GEM
     certified (1.0.0)
     climate_control (0.2.0)
     coderay (1.1.2)
-    concurrent-ruby (1.1.6)
-    connection_pool (2.2.2)
+    concurrent-ruby (1.1.9)
+    connection_pool (2.2.5)
     coveralls (0.8.23)
       json (>= 1.8, < 3)
       simplecov (~> 0.16.1)
@@ -229,11 +229,10 @@ GEM
       sequel (>= 4.38.0)
     shotgun (0.9.2)
       rack (>= 1.0)
-    sidekiq (4.2.10)
-      concurrent-ruby (~> 1.0)
-      connection_pool (~> 2.2, >= 2.2.0)
+    sidekiq (5.2.0)
+      connection_pool (~> 2.2, >= 2.2.2)
       rack-protection (>= 1.5.0)
-      redis (~> 3.2, >= 3.2.1)
+      redis (>= 3.3.5, < 5)
     simplecov (0.16.1)
       docile (~> 1.1)
       json (>= 1.8, < 3)
@@ -352,7 +351,7 @@ DEPENDENCIES
   sequel
   sequel_pg
   shotgun
-  sidekiq (~> 4.2.10)
+  sidekiq (~> 5.2.0)
   simplecov
   simpleidn
   sinatra (= 2.0.5)