diff --git a/Gemfile b/Gemfile
index 4041f02e4..447b27e5f 100644
--- a/Gemfile
+++ b/Gemfile
@@ -33,7 +33,7 @@ gem "simple_captcha2", "0.4.0", require: "simple_captcha"
 
 # Background processing
 
-gem "sidekiq", "4.1.4"
+gem "sidekiq", "4.2.2"
 gem "sinatra", "1.4.7"
 
 # Scheduled processing
diff --git a/Gemfile.lock b/Gemfile.lock
index c51986c53..8e2969ebc 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -784,11 +784,11 @@ GEM
     shellany (0.0.1)
     shoulda-matchers (3.1.1)
       activesupport (>= 4.0.0)
-    sidekiq (4.1.4)
+    sidekiq (4.2.2)
       concurrent-ruby (~> 1.0)
       connection_pool (~> 2.2, >= 2.2.0)
+      rack-protection (~> 1.5)
       redis (~> 3.2, >= 3.2.1)
-      sinatra (>= 1.4.7)
     sidekiq-cron (0.4.2)
       redis-namespace (>= 1.5.2)
       rufus-scheduler (>= 2.0.24)
@@ -1029,7 +1029,7 @@ DEPENDENCIES
   sass-rails (= 5.0.6)
   secure_headers (= 3.4.1)
   shoulda-matchers (= 3.1.1)
-  sidekiq (= 4.1.4)
+  sidekiq (= 4.2.2)
   sidekiq-cron (= 0.4.2)
   simple_captcha2 (= 0.4.0)
   simplecov (= 0.12.0)