diff --git a/Gemfile b/Gemfile
index 323309b9..394a0c62 100644
--- a/Gemfile
+++ b/Gemfile
@@ -30,7 +30,7 @@ gem 'jquery-rails'
 gem 'underscore-rails'
 
 # Sidekiq and its dependencies
-gem 'sidekiq', '< 3'
+gem 'sidekiq', '< 6'
 gem 'slim'
 gem 'sinatra', require: false
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 9ffac4b1..2e022d1a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -58,8 +58,6 @@ GEM
       activesupport (>= 3.2.0)
       json (>= 1.7)
       mime-types (>= 1.16)
-    celluloid (0.15.2)
-      timers (~> 1.1.0)
     coderay (1.1.0)
     coffee-rails (4.2.2)
       coffee-script (>= 2.2.0)
@@ -69,7 +67,7 @@ GEM
       execjs
     coffee-script-source (1.12.2)
     concurrent-ruby (1.1.9)
-    connection_pool (2.2.0)
+    connection_pool (2.2.5)
     coveralls (0.8.2)
       json (~> 1.8)
       rest-client (>= 1.6.8, < 2)
@@ -249,9 +247,7 @@ GEM
     rb-inotify (0.9.5)
       ffi (>= 0.5.0)
     rdiscount (2.2.0.2)
-    redis (3.2.1)
-    redis-namespace (1.5.2)
-      redis (~> 3.0, >= 3.0.4)
+    redis (4.4.0)
     request_store (1.2.0)
     responders (2.4.0)
       actionpack (>= 4.2.0, < 5.3)
@@ -305,12 +301,10 @@ GEM
     shellany (0.0.1)
     shoulda-matchers (2.8.0)
       activesupport (>= 3.0.0)
-    sidekiq (2.17.8)
-      celluloid (= 0.15.2)
-      connection_pool (~> 2.0)
-      json
-      redis (~> 3.1)
-      redis-namespace (~> 1.3)
+    sidekiq (5.2.0)
+      connection_pool (~> 2.2, >= 2.2.2)
+      rack-protection (>= 1.5.0)
+      redis (>= 3.3.5, < 5)
     simple_form (3.1.0)
       actionpack (~> 4.0)
       activemodel (~> 4.0)
@@ -349,7 +343,6 @@ GEM
     thread_safe (0.3.6)
     tilt (1.4.1)
     timecop (0.8.0)
-    timers (1.1.0)
     tins (1.6.0)
     tzinfo (1.2.9)
       thread_safe (~> 0.1)
@@ -418,7 +411,7 @@ DEPENDENCIES
   sass (~> 3.2.0)
   sass-rails (~> 4.0)
   shoulda-matchers
-  sidekiq (< 3)
+  sidekiq (< 6)
   simple_form
   simplecov
   sinatra