diff --git a/Gemfile b/Gemfile
index e03a3070..48ca8c1e 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,4 +9,4 @@ gem 'wdm', '>= 0.1.1' if Gem.win_platform?
 
 gem "webrick", "~> 1.7"
 
-gem 'html-proofer', "~> 3.19.4"
+gem 'html-proofer', "~> 4.0.1"
diff --git a/Gemfile.lock b/Gemfile.lock
index fb415893..8fac13e7 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -107,7 +107,7 @@ GEM
     html-pipeline (2.14.1)
       activesupport (>= 2)
       nokogiri (>= 1.4)
-    html-proofer (3.19.4)
+    html-proofer (4.0.1)
       addressable (~> 2.3)
       mercenary (~> 0.3)
       nokogiri (~> 1.13)
@@ -115,6 +115,7 @@ GEM
       rainbow (~> 3.0)
       typhoeus (~> 1.3)
       yell (~> 2.0)
+      zeitwerk (~> 2.5)
     http_parser.rb (0.8.0)
     i18n (0.9.5)
       concurrent-ruby (~> 1.0)
@@ -296,7 +297,7 @@ PLATFORMS
 
 DEPENDENCIES
   github-pages (= 226)
-  html-proofer (~> 3.19.4)
+  html-proofer (~> 4.0.1)
   webrick (~> 1.7)
 
 BUNDLED WITH