diff --git a/docker/exercises/sample_app/Gemfile b/docker/exercises/sample_app/Gemfile
index 1d0a7a4..dcbd828 100644
--- a/docker/exercises/sample_app/Gemfile
+++ b/docker/exercises/sample_app/Gemfile
@@ -18,7 +18,7 @@ gem 'redis', '~> 4.0', '>= 4.0.2'
 gem 'sidekiq', '~> 5.2', '>= 5.2.1'
 gem 'dalli', '~> 2.7', '>= 2.7.8'
 gem 'memcachier', '~> 0.0.2'
-gem 'nokogiri', '~> 1.8', '>= 1.8.4'
+gem 'nokogiri', '~> 1.11'
 
 group :development, :test do
 end
diff --git a/docker/exercises/sample_app/Gemfile.lock b/docker/exercises/sample_app/Gemfile.lock
index 02facfa..bc4c249 100644
--- a/docker/exercises/sample_app/Gemfile.lock
+++ b/docker/exercises/sample_app/Gemfile.lock
@@ -107,15 +107,18 @@ GEM
       mimemagic (~> 0.3.2)
     memcachier (0.0.2)
     method_source (0.9.0)
-    mimemagic (0.3.2)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.1)
-    mini_portile2 (2.3.0)
+    mini_portile2 (2.5.1)
     minitest (5.11.3)
     msgpack (1.2.4)
     multi_json (1.13.1)
     nio4r (2.3.1)
-    nokogiri (1.8.4)
-      mini_portile2 (~> 2.3.0)
+    nokogiri (1.11.4)
+      mini_portile2 (~> 2.5.0)
+      racc (~> 1.4)
     pg (1.1.0)
     pry (0.11.3)
       coderay (~> 1.1.0)
@@ -124,6 +127,7 @@ GEM
       pry (>= 0.10.4)
     public_suffix (3.0.3)
     puma (3.12.0)
+    racc (1.5.2)
     rack (2.0.5)
     rack-protection (2.0.3)
       rack
@@ -225,7 +229,7 @@ DEPENDENCIES
   jquery-rails (~> 4.3, >= 4.3.3)
   listen (>= 3.0.5, < 3.2)
   memcachier (~> 0.0.2)
-  nokogiri (~> 1.8, >= 1.8.4)
+  nokogiri (~> 1.11)
   pg (>= 0.18, < 2.0)
   pry-rails (~> 0.3.6)
   puma (~> 3.11)