diff --git a/Gemfile b/Gemfile
index 8c7e1e27..8cfbd280 100644
--- a/Gemfile
+++ b/Gemfile
@@ -7,7 +7,7 @@ gem 'wdm', '~> 0.1.0', platforms: [:mswin, :mingw]
 gem 'tzinfo-data', platforms: [:mswin, :mingw, :jruby]
 
 # Include the tech docs gem
-gem 'govuk_tech_docs', "~> 3.5"
+gem 'govuk_tech_docs', "~> 4.1"
 
 # The search functionality requires the `middleman-search` gem
 gem 'middleman-search-gds', git: 'https://github.com/alphagov/middleman-search.git'
diff --git a/Gemfile.lock b/Gemfile.lock
index 4d0b6a68..0f39a058 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -10,16 +10,18 @@ GIT
 GEM
   remote: https://rubygems.org/
   specs:
-    activesupport (7.0.8.1)
+    activesupport (7.0.8.6)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 1.6, < 2)
       minitest (>= 5.1)
       tzinfo (~> 2.0)
-    addressable (2.8.6)
-      public_suffix (>= 2.0.2, < 6.0)
-    autoprefixer-rails (10.4.16.0)
+    addressable (2.8.7)
+      public_suffix (>= 2.0.2, < 7.0)
+    autoprefixer-rails (10.4.19.0)
       execjs (~> 2)
-    backports (3.24.1)
+    backports (3.25.0)
+    base64 (0.2.0)
+    bigdecimal (3.1.8)
     chronic (0.10.2)
     chunky_png (1.4.0)
     coffee-script (2.4.1)
@@ -39,34 +41,45 @@ GEM
       sass (>= 3.3.0, < 3.5)
     compass-import-once (1.0.5)
       sass (>= 3.2, < 3.5)
-    concurrent-ruby (1.2.3)
+    concurrent-ruby (1.3.4)
     contracts (0.16.1)
-    dotenv (3.0.2)
+    csv (3.3.0)
+    dotenv (3.1.4)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
     erubis (2.7.0)
     eventmachine (1.2.7)
-    execjs (2.9.1)
+    execjs (2.10.0)
     fast_blank (1.0.1)
-    fastimage (2.3.0)
-    ffi (1.16.3)
-    govuk_tech_docs (3.5.0)
+    fastimage (2.3.1)
+    ffi (1.17.0)
+    google-protobuf (4.28.3)
+      bigdecimal
+      rake (>= 13)
+    govuk_tech_docs (4.1.0)
       autoprefixer-rails (~> 10.2)
+      base64
+      bigdecimal
       chronic (~> 0.10.2)
-      haml (< 6.0.0)
+      csv
+      haml (~> 6.0)
       middleman (~> 4.0)
-      middleman-autoprefixer (~> 2.10.0)
-      middleman-compass (>= 4.0.0)
+      middleman-autoprefixer (~> 2.10)
+      middleman-compass (~> 4.0)
       middleman-livereload
       middleman-search-gds
       middleman-sprockets (~> 4.0.0)
-      middleman-syntax (~> 3.2.0)
+      middleman-syntax (~> 3.4)
+      mutex_m
       nokogiri
       openapi3_parser (~> 0.9.0)
-      redcarpet (~> 3.5.1)
-    haml (5.2.2)
-      temple (>= 0.8.0)
+      redcarpet (~> 3.6)
+      sassc-embedded (~> 1.78.0)
+      terser (~> 1.2.3)
+    haml (6.3.0)
+      temple (>= 0.8.2)
+      thor
       tilt
     hamster (3.0.0)
       concurrent-ruby (~> 1.0)
@@ -76,7 +89,7 @@ GEM
       concurrent-ruby (~> 1.0)
     kramdown (2.4.0)
       rexml
-    listen (3.8.0)
+    listen (3.9.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     memoist (0.16.2)
@@ -126,13 +139,14 @@ GEM
     middleman-sprockets (4.0.0)
       middleman-core (~> 4.0)
       sprockets (>= 3.0)
-    middleman-syntax (3.2.0)
+    middleman-syntax (3.4.0)
       middleman-core (>= 3.2)
       rouge (~> 3.2)
-    mini_portile2 (2.8.6)
-    minitest (5.22.2)
+    mini_portile2 (2.8.7)
+    minitest (5.25.1)
     multi_json (1.15.0)
-    nokogiri (1.16.5)
+    mutex_m (0.2.0)
+    nokogiri (1.16.7)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
     openapi3_parser (0.9.2)
@@ -142,27 +156,35 @@ GEM
       padrino-support (= 0.15.3)
       tilt (>= 1.4.1, < 3)
     padrino-support (0.15.3)
-    parallel (1.24.0)
+    parallel (1.26.3)
     parslet (2.0.0)
-    public_suffix (5.0.4)
-    racc (1.7.3)
-    rack (2.2.8.1)
+    public_suffix (6.0.1)
+    racc (1.8.1)
+    rack (2.2.10)
     rack-livereload (0.3.17)
       rack
+    rake (13.2.1)
     rb-fsevent (0.11.2)
-    rb-inotify (0.10.1)
+    rb-inotify (0.11.1)
       ffi (~> 1.0)
-    redcarpet (3.5.1)
-    rexml (3.2.6)
+    redcarpet (3.6.0)
+    rexml (3.3.9)
     rouge (3.30.0)
     sass (3.4.25)
+    sass-embedded (1.80.6)
+      google-protobuf (~> 4.28)
+      rake (>= 13)
     sassc (2.4.0)
       ffi (~> 1.9)
+    sassc-embedded (1.78.0)
+      sass-embedded (~> 1.78)
     servolux (0.13.0)
     sprockets (4.2.1)
       concurrent-ruby (~> 1.0)
       rack (>= 2.2.4, < 4)
     temple (0.10.3)
+    terser (1.2.4)
+      execjs (>= 0.3.0, < 3)
     thor (1.2.2)
     tilt (2.0.11)
     toml (0.3.0)
@@ -177,7 +199,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
-  govuk_tech_docs (~> 3.5)
+  govuk_tech_docs (~> 4.1)
   middleman-search-gds!
   tzinfo-data
   wdm (~> 0.1.0)