diff --git a/.ruby-version b/.ruby-version
index 2c9b4ef..15a2799 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.7.3
+3.3.0
diff --git a/Gemfile b/Gemfile
index 771adb5..2245f10 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,11 +2,13 @@ source 'https://rubygems.org'
 
 gem 'rake'
 gem 'kramdown'
-# Pin to the version used on GitHub Pages
-gem 'jekyll', 3.9
+gem 'jekyll', '~> 3'
 
 # For testing output
-gem 'html-proofer'
+gem 'html-proofer', '~> 3'
+
+# Avoid polling on windows
+gem 'wdm', '>= 0.1.0'
 
 # For local Ruby 3 support; works around https://github.com/github/pages-gem/issues/752
 gem "webrick", "~> 1.7"
diff --git a/Gemfile.lock b/Gemfile.lock
index 87845ec..36e7eaf 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,34 +1,38 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.8.0)
-      public_suffix (>= 2.0.2, < 5.0)
+    addressable (2.8.6)
+      public_suffix (>= 2.0.2, < 6.0)
     colorator (1.1.0)
-    concurrent-ruby (1.1.8)
-    em-websocket (0.5.2)
+    concurrent-ruby (1.2.3)
+    em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
-      http_parser.rb (~> 0.6.0)
-    ethon (0.15.0)
+      http_parser.rb (~> 0)
+    ethon (0.16.0)
       ffi (>= 1.15.0)
     eventmachine (1.2.7)
-    ffi (1.15.5)
+    eventmachine (1.2.7-x64-mingw32)
+    eventmachine (1.2.7-x86-mingw32)
+    ffi (1.16.3)
+    ffi (1.16.3-x64-mingw32)
+    ffi (1.16.3-x86-mingw32)
     forwardable-extended (2.6.0)
-    html-proofer (3.19.2)
+    html-proofer (3.19.4)
       addressable (~> 2.3)
       mercenary (~> 0.3)
-      nokogumbo (~> 2.0)
-      parallel (~> 1.3)
+      nokogiri (~> 1.13)
+      parallel (~> 1.10)
       rainbow (~> 3.0)
       typhoeus (~> 1.3)
       yell (~> 2.0)
-    http_parser.rb (0.6.0)
-    i18n (0.9.5)
+    http_parser.rb (0.8.0)
+    i18n (1.14.4)
       concurrent-ruby (~> 1.0)
-    jekyll (3.9.0)
+    jekyll (3.9.5)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
-      i18n (~> 0.7)
+      i18n (>= 0.7, < 2)
       jekyll-sass-converter (~> 1.0)
       jekyll-watch (~> 2.0)
       kramdown (>= 1.17, < 3)
@@ -41,10 +45,10 @@ GEM
       sass (~> 3.4)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (2.3.1)
+    kramdown (2.4.0)
       rexml
-    liquid (4.0.3)
-    listen (3.7.1)
+    liquid (4.0.4)
+    listen (3.9.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.3.6)
@@ -52,40 +56,46 @@ GEM
     nokogiri (1.15.6)
       mini_portile2 (~> 2.8.2)
       racc (~> 1.4)
-    nokogumbo (2.0.5)
-      nokogiri (~> 1.8, >= 1.8.4)
-    parallel (1.21.0)
+    nokogiri (1.15.6-x64-mingw32)
+      racc (~> 1.4)
+    nokogiri (1.15.6-x86-mingw32)
+      racc (~> 1.4)
+    parallel (1.24.0)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
-    public_suffix (4.0.6)
+    public_suffix (5.0.4)
     racc (1.7.3)
-    rainbow (3.0.0)
+    rainbow (3.1.1)
     rake (12.3.3)
-    rb-fsevent (0.11.0)
+    rb-fsevent (0.11.2)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.5)
-    rouge (3.26.0)
+    rexml (3.2.6)
+    rouge (3.30.0)
     safe_yaml (1.0.5)
     sass (3.7.4)
       sass-listen (~> 4.0.0)
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
-    typhoeus (1.4.0)
+    typhoeus (1.4.1)
       ethon (>= 0.9.0)
+    wdm (0.1.1)
     webrick (1.7.0)
     yell (2.2.2)
 
 PLATFORMS
   ruby
+  x64-mingw32
+  x86-mingw32
 
 DEPENDENCIES
-  html-proofer
-  jekyll (= 3.9)
+  html-proofer (~> 3)
+  jekyll (~> 3)
   kramdown
   rake
+  wdm (>= 0.1.0)
   webrick (~> 1.7)
 
 BUNDLED WITH
-   2.1.4
+   2.3.6
diff --git a/README.md b/README.md
index 00717e3..8693ca1 100644
--- a/README.md
+++ b/README.md
@@ -15,11 +15,16 @@ SRComp-HTTP instance separately.
 
 1. [Clone this repo][clone-repo]
 
-1. [Install Ruby][install-ruby]
+1. [Install Ruby 3][install-ruby]
 
-1. Install Bundler (2.x) and Rake
+   See `.ruby_version` for the precise version, though 3.3 or above will
+   probably be fine.
 
-    ``` shell
+1. Install Bundler (2.3 or above) and Rake.
+
+   Depending on how you have installed Ruby these may already be installed.
+
+    ``` console
     $ gem install bundler rake
     ```