diff --git a/.gitattributes b/.gitattributes
index 1a84f9ea8..75bb2414a 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -1,4 +1,5 @@
-
 *.min.*               binary
+*.svg                 binary
+
 # GitHub syntax highlighting
 pixi.lock linguist-language=YAML linguist-generated=true
diff --git a/.github/actions/prepare-build-site/action.yml b/.github/actions/prepare-build-site/action.yml
index a8e39fc6c..12391e51d 100644
--- a/.github/actions/prepare-build-site/action.yml
+++ b/.github/actions/prepare-build-site/action.yml
@@ -4,7 +4,7 @@ inputs:
   ruby-version:
     description: "Version of ruby to prepare"
     required: false
-    default: "3.1"
+    default: "3.4"
 
 runs:
   using: composite
@@ -13,9 +13,9 @@ runs:
       uses: actions/cache@v3
       with:
         path: vendor/bundle
-        key: ${{ runner.os }}-gems-${{ hashFiles('**/Gemfile.lock') }}
+        key: ${{ runner.os }}-gems-${{ inputs.ruby-version }}-${{ hashFiles('**/Gemfile.lock') }}
         restore-keys: |
-          ${{ runner.os }}-gems-
+          ${{ runner.os }}-gems-${{ inputs.ruby-version }}-
 
     - name: Restore publication cache
       uses: actions/cache@v3
diff --git a/.rubocop.yml b/.rubocop.yml
index 7eb5d7ff0..6e4f6275a 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -14,4 +14,6 @@ Metrics/CyclomaticComplexity:
   Max: 12
 AllCops:
   NewCops: enable
-  TargetRubyVersion: 2.6
+  TargetRubyVersion: 3.1
+plugins:
+  - rubocop-rake
diff --git a/Gemfile b/Gemfile
index ea4cebda8..2fe2accdf 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,7 +2,7 @@
 
 source 'https://rubygems.org'
 
-ruby '>= 2.6.0'
+ruby '>= 3.1.0'
 
 # Hello! This is where you manage which Jekyll version is used to run.
 # When you want to use a different version, change it below, save the
@@ -12,7 +12,7 @@ ruby '>= 2.6.0'
 #
 # This will help ensure the proper Jekyll version is running.
 # Happy Jekylling!
-gem 'jekyll', '~> 4.2.0'
+gem 'jekyll'
 
 # This is needed for GitHub Flavored Markdown
 gem 'kramdown-parser-gfm'
@@ -25,20 +25,24 @@ group :development do
   gem 'rake', require: false
 
   # Verify good coding practices in Ruby files
-  gem 'rubocop', '~>1.25.0', require: false
+  gem 'rubocop', require: false
 
   # Extension for Rake files
   gem 'rubocop-rake', require: false
 end
 
 # This is the default theme for new Jekyll sites. You may change this to anything you like.
-gem 'minima', '~> 2.5'
+gem 'minima'
+
+# Removed from the stdlib
+gem 'benchmark'
+gem 'logger'
 
 # If you have any plugins, put them here!
 group :jekyll_plugins do
-  gem 'jekyll-feed', '~> 0.16'
+  gem 'jekyll-feed'
   gem 'jekyll-include-cache'
-  gem 'jekyll-indico', '~> 0.6.2'
+  gem 'jekyll-indico'
   # gem 'jekyll-indico', github: 'iris-hep/jekyll-indico', branch: 'main'
 end
 
@@ -49,10 +53,10 @@ gem 'jekyll-last-modified-at'
 gem 'tzinfo-data', platforms: %i[mingw mswin x64_mingw jruby]
 
 # Needed by Nokogiri
-gem 'pkg-config', '~> 1.4'
+gem 'pkg-config'
 
 # Performance-booster for watching directories on Windows
-gem 'wdm', '~> 0.1.0' if Gem.win_platform?
+gem 'wdm' if Gem.win_platform?
 
 # Required on Ruby 3+ (next Jekyll will fix this missing dep)
 gem 'webrick'
diff --git a/Gemfile.lock b/Gemfile.lock
index 80de9a6b5..e925185bd 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,47 +1,95 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    Ascii85 (2.0.1)
     addressable (2.8.7)
       public_suffix (>= 2.0.2, < 7.0)
+    afm (0.2.2)
     ast (2.4.2)
+    async (2.23.0)
+      console (~> 1.29)
+      fiber-annotation
+      io-event (~> 1.9)
+      metrics (~> 0.12)
+      traces (~> 0.15)
+    base64 (0.2.0)
+    benchmark (0.4.0)
+    bigdecimal (3.1.9)
     colorator (1.1.0)
-    concurrent-ruby (1.3.3)
-    diff-lcs (1.5.0)
+    concurrent-ruby (1.3.5)
+    console (1.29.3)
+      fiber-annotation
+      fiber-local (~> 1.1)
+      json
+    csv (3.3.2)
+    diff-lcs (1.6.0)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
     ethon (0.16.0)
       ffi (>= 1.15.0)
     eventmachine (1.2.7)
-    ffi (1.17.0)
+    ffi (1.17.1-aarch64-linux-gnu)
+    ffi (1.17.1-aarch64-linux-musl)
+    ffi (1.17.1-arm-linux-gnu)
+    ffi (1.17.1-arm-linux-musl)
+    ffi (1.17.1-arm64-darwin)
+    ffi (1.17.1-x86_64-darwin)
+    ffi (1.17.1-x86_64-linux-gnu)
+    ffi (1.17.1-x86_64-linux-musl)
+    fiber-annotation (0.2.0)
+    fiber-local (1.1.0)
+      fiber-storage
+    fiber-storage (1.0.0)
     forwardable-extended (2.6.0)
-    html-proofer (4.4.3)
+    google-protobuf (4.29.3)
+      bigdecimal
+      rake (>= 13)
+    google-protobuf (4.29.3-aarch64-linux)
+      bigdecimal
+      rake (>= 13)
+    google-protobuf (4.29.3-arm64-darwin)
+      bigdecimal
+      rake (>= 13)
+    google-protobuf (4.29.3-x86_64-darwin)
+      bigdecimal
+      rake (>= 13)
+    google-protobuf (4.29.3-x86_64-linux)
+      bigdecimal
+      rake (>= 13)
+    hashery (2.1.2)
+    html-proofer (5.0.10)
       addressable (~> 2.3)
-      mercenary (~> 0.3)
+      async (~> 2.1)
       nokogiri (~> 1.13)
-      parallel (~> 1.10)
+      pdf-reader (~> 2.11)
       rainbow (~> 3.0)
       typhoeus (~> 1.3)
       yell (~> 2.0)
       zeitwerk (~> 2.5)
     http_parser.rb (0.8.0)
-    i18n (1.14.5)
+    i18n (1.14.7)
       concurrent-ruby (~> 1.0)
-    jekyll (4.2.2)
+    io-event (1.9.0)
+    jekyll (4.4.1)
       addressable (~> 2.4)
+      base64 (~> 0.2)
       colorator (~> 1.0)
+      csv (~> 3.0)
       em-websocket (~> 0.5)
       i18n (~> 1.0)
-      jekyll-sass-converter (~> 2.0)
+      jekyll-sass-converter (>= 2.0, < 4.0)
       jekyll-watch (~> 2.0)
-      kramdown (~> 2.3)
+      json (~> 2.6)
+      kramdown (~> 2.3, >= 2.3.1)
       kramdown-parser-gfm (~> 1.0)
       liquid (~> 4.0)
-      mercenary (~> 0.4.0)
+      mercenary (~> 0.3, >= 0.3.6)
       pathutil (~> 0.9)
-      rouge (~> 3.0)
+      rouge (>= 3.0, < 5.0)
       safe_yaml (~> 1.0)
-      terminal-table (~> 2.0)
+      terminal-table (>= 1.8, < 4.0)
+      webrick (~> 1.7)
     jekyll-feed (0.17.0)
       jekyll (>= 3.7, < 5.0)
     jekyll-include-cache (0.2.1)
@@ -50,110 +98,165 @@ GEM
       jekyll (>= 3.8, < 5.0)
     jekyll-last-modified-at (1.3.2)
       jekyll (>= 3.7, < 5.0)
-    jekyll-sass-converter (2.2.0)
-      sassc (> 2.0.1, < 3.0)
+    jekyll-sass-converter (3.1.0)
+      sass-embedded (~> 1.75)
     jekyll-seo-tag (2.8.0)
       jekyll (>= 3.8, < 5.0)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (2.4.0)
-      rexml
+    json (2.10.1)
+    kramdown (2.5.1)
+      rexml (>= 3.3.9)
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
+    language_server-protocol (3.17.0.4)
+    lint_roller (1.1.0)
     liquid (4.0.4)
     listen (3.9.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
+    logger (1.6.6)
     mercenary (0.4.0)
-    mini_portile2 (2.8.8)
-    minima (2.5.1)
+    metrics (0.12.1)
+    minima (2.5.2)
       jekyll (>= 3.5, < 5.0)
       jekyll-feed (~> 0.9)
       jekyll-seo-tag (~> 2.1)
-    nokogiri (1.18.3)
-      mini_portile2 (~> 2.8.2)
+    nokogiri (1.18.3-aarch64-linux-gnu)
+      racc (~> 1.4)
+    nokogiri (1.18.3-aarch64-linux-musl)
+      racc (~> 1.4)
+    nokogiri (1.18.3-arm-linux-gnu)
+      racc (~> 1.4)
+    nokogiri (1.18.3-arm-linux-musl)
+      racc (~> 1.4)
+    nokogiri (1.18.3-arm64-darwin)
       racc (~> 1.4)
     nokogiri (1.18.3-x86_64-darwin)
       racc (~> 1.4)
     nokogiri (1.18.3-x86_64-linux-gnu)
       racc (~> 1.4)
-    parallel (1.22.1)
-    parser (3.1.3.0)
+    nokogiri (1.18.3-x86_64-linux-musl)
+      racc (~> 1.4)
+    paco (0.2.3)
+    parallel (1.26.3)
+    parser (3.3.7.1)
       ast (~> 2.4.1)
+      racc
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
-    pkg-config (1.5.1)
+    pdf-reader (2.14.1)
+      Ascii85 (>= 1.0, < 3.0, != 2.0.0)
+      afm (~> 0.2.1)
+      hashery (~> 2.0)
+      ruby-rc4
+      ttfunk
+    pkg-config (1.6.0)
     public_suffix (6.0.1)
     racc (1.8.1)
     rainbow (3.1.1)
-    rake (13.0.6)
+    rake (13.2.1)
     rb-fsevent (0.11.2)
     rb-inotify (0.11.1)
       ffi (~> 1.0)
-    regexp_parser (2.6.1)
-    rexml (3.3.9)
-    rouge (3.30.0)
-    rubocop (1.25.1)
+    regexp_parser (2.10.0)
+    require-hooks (0.2.2)
+    rexml (3.4.1)
+    rouge (4.5.1)
+    rubocop (1.73.1)
+      json (~> 2.3)
+      language_server-protocol (~> 3.17.0.2)
+      lint_roller (~> 1.1.0)
       parallel (~> 1.10)
-      parser (>= 3.1.0.0)
+      parser (>= 3.3.0.2)
       rainbow (>= 2.2.2, < 4.0)
-      regexp_parser (>= 1.8, < 3.0)
-      rexml
-      rubocop-ast (>= 1.15.1, < 2.0)
+      regexp_parser (>= 2.9.3, < 3.0)
+      rubocop-ast (>= 1.38.0, < 2.0)
       ruby-progressbar (~> 1.7)
-      unicode-display_width (>= 1.4.0, < 3.0)
-    rubocop-ast (1.24.0)
-      parser (>= 3.1.1.0)
-    rubocop-rake (0.6.0)
-      rubocop (~> 1.0)
-    ruby-next (0.15.3)
-      ruby-next-core (= 0.15.3)
-      ruby-next-parser (>= 3.1.1.0)
+      unicode-display_width (>= 2.4.0, < 4.0)
+    rubocop-ast (1.38.1)
+      parser (>= 3.3.1.0)
+    rubocop-rake (0.7.1)
+      lint_roller (~> 1.1)
+      rubocop (>= 1.72.1)
+    ruby-next (1.1.1)
+      paco (~> 0.2)
+      require-hooks (~> 0.2)
+      ruby-next-core (= 1.1.1)
+      ruby-next-parser (>= 3.4.0.2)
       unparser (~> 0.6.0)
-    ruby-next-core (0.15.3)
-    ruby-next-parser (3.1.1.3)
+    ruby-next-core (1.1.1)
+    ruby-next-parser (3.4.0.2)
       parser (>= 3.0.3.1)
-    ruby-progressbar (1.11.0)
+    ruby-progressbar (1.13.0)
+    ruby-rc4 (0.1.5)
     safe_yaml (1.0.5)
-    sassc (2.4.0)
-      ffi (~> 1.9)
-    terminal-table (2.0.0)
-      unicode-display_width (~> 1.1, >= 1.1.1)
-    typhoeus (1.4.0)
+    sass-embedded (1.85.1-aarch64-linux-gnu)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-aarch64-linux-musl)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-arm-linux-gnueabihf)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-arm-linux-musleabihf)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-arm64-darwin)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-x86_64-darwin)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-x86_64-linux-gnu)
+      google-protobuf (~> 4.29)
+    sass-embedded (1.85.1-x86_64-linux-musl)
+      google-protobuf (~> 4.29)
+    terminal-table (3.0.2)
+      unicode-display_width (>= 1.1.1, < 3)
+    traces (0.15.2)
+    ttfunk (1.8.0)
+      bigdecimal (~> 3.1)
+    typhoeus (1.4.1)
       ethon (>= 0.9.0)
-    unicode-display_width (1.8.0)
-    unparser (0.6.4)
+    unicode-display_width (2.6.0)
+    unparser (0.6.15)
       diff-lcs (~> 1.3)
-      parser (>= 3.1.0)
-    webrick (1.8.2)
+      parser (>= 3.3.0)
+    webrick (1.9.1)
     yell (2.2.2)
-    zeitwerk (2.6.6)
+    zeitwerk (2.7.2)
 
 PLATFORMS
-  ruby
-  x86_64-darwin-20
-  x86_64-darwin-21
+  aarch64-linux
+  aarch64-linux-gnu
+  aarch64-linux-musl
+  arm-linux-gnu
+  arm-linux-gnueabihf
+  arm-linux-musl
+  arm-linux-musleabihf
+  arm64-darwin
+  x86_64-darwin
   x86_64-linux
+  x86_64-linux-gnu
+  x86_64-linux-musl
 
 DEPENDENCIES
+  benchmark
   html-proofer
-  jekyll (~> 4.2.0)
-  jekyll-feed (~> 0.16)
+  jekyll
+  jekyll-feed
   jekyll-include-cache
-  jekyll-indico (~> 0.6.2)
+  jekyll-indico
   jekyll-last-modified-at
   kramdown-parser-gfm
-  minima (~> 2.5)
-  pkg-config (~> 1.4)
+  logger
+  minima
+  pkg-config
   rake
-  rubocop (~> 1.25.0)
+  rubocop
   rubocop-rake
   ruby-next
   tzinfo-data
   webrick
 
 RUBY VERSION
-   ruby 2.7.3p183
+   ruby 3.4.1p0
 
 BUNDLED WITH
-   2.3.13
+   2.6.5
diff --git a/_plugins/checks_extend.rb b/_plugins/checks_extend.rb
index 8d6e42d7a..d06603082 100644
--- a/_plugins/checks_extend.rb
+++ b/_plugins/checks_extend.rb
@@ -7,7 +7,7 @@ def focus_areas
       @focus_areas ||= begin
         extras = @site.config['iris-hep']['extra-focus-areas'].to_set
         focus_area_pages = @site.pages.select { |p| p['pagetype'] == 'focus-area' }
-        locals = focus_area_pages.map { |p| File.basename(p.name, '.*') }.to_set
+        locals = focus_area_pages.to_set { |p| File.basename(p.name, '.*') }
         extras | locals
       end
     end
@@ -19,14 +19,14 @@ def projects
           msg = "Filename #{p.name} must match the shortname #{p['shortname']}"
           raise Checks::Error, msg unless File.basename(p.name, '.*') == p['shortname']
         end
-        project_pages.map { |p| File.basename(p.name, '.*') }.to_set
+        project_pages.to_set { |p| File.basename(p.name, '.*') }
       end
     end
 
     def challenge_areas
       @challenge_areas ||= begin
         challenge_area_pages = @site.pages.select { |p| p['pagetype'] == 'challenge-area' }
-        challenge_area_pages.map { |p| File.basename(p.name, '.*') }.to_set
+        challenge_area_pages.to_set { |p| File.basename(p.name, '.*') }
       end
     end
 
diff --git a/_plugins/checkusers.rb b/_plugins/checkusers.rb
index cef49516d..de0efc9e2 100755
--- a/_plugins/checkusers.rb
+++ b/_plugins/checkusers.rb
@@ -11,7 +11,7 @@ def generate(site)
       @site = site
 
       people_in_inst = Set.new
-      @site.data['universities'].each do |_inst_name, inst_hash|
+      @site.data['universities'].each_value do |inst_hash|
         people_in_inst.merge inst_hash['personnel']
       end
 
diff --git a/_plugins/gantt.rb b/_plugins/gantt.rb
index b1fe0af00..d502222bb 100644
--- a/_plugins/gantt.rb
+++ b/_plugins/gantt.rb
@@ -1,11 +1,5 @@
 # frozen_string_literal: true
 
-if Gem.ruby_version < Gem::Version.new('2.7.0')
-  # Add filter_map
-  require 'ruby-next'
-  using RubyNext
-end
-
 def process_projects(projects)
   projects.filter_map do |project|
     project['start-date'] && {
diff --git a/_plugins/getpub.rb b/_plugins/getpub.rb
index aa9662f09..d83b9e915 100755
--- a/_plugins/getpub.rb
+++ b/_plugins/getpub.rb
@@ -228,7 +228,7 @@ def inspire(pub)
       # Build the citation string (non-author part)
       j = data.dig('publication_info', 0) # This may be nil
       journal =
-        if j&.key?('journal_title') && j&.key?('year')
+        if j&.key?('journal_title') && j.key?('year')
           pub['needs-nsf-par'] = true unless pub.key?('needs-nsf-par')
           "#{j['journal_title']} #{j['journal_volume']} #{j['artid']} (#{j['year']})"
         elsif data.key? 'arxiv_eprints'
diff --git a/_scripts/challenge_area.rb b/_scripts/challenge_area.rb
index 013549a1b..674096371 100644
--- a/_scripts/challenge_area.rb
+++ b/_scripts/challenge_area.rb
@@ -32,7 +32,7 @@ def ensure_array(arr)
   all_fa = (user_fa || Set.new) | (proj_fa || Set.new)
   info['challenge-area'] = all_fa.to_a unless all_fa.empty?
 
-  sorted = info.sort_by { _1 }.to_h
+  sorted = info.sort.to_h
   sorted['presentations'] = sorted.delete 'presentations'
 
   fn.write(sorted.to_yaml.lines[1..].join)
diff --git a/_scripts/focus_area.rb b/_scripts/focus_area.rb
index b76875885..f391ddad6 100644
--- a/_scripts/focus_area.rb
+++ b/_scripts/focus_area.rb
@@ -32,7 +32,7 @@ def ensure_array(arr)
   all_fa = (user_fa || Set.new) | (proj_fa || Set.new)
   info['focus-area'] = all_fa.to_a unless all_fa.empty?
 
-  sorted = info.sort_by { _1 }.to_h
+  sorted = info.sort.to_h
   sorted['presentations'] = sorted.delete 'presentations'
 
   fn.write(sorted.to_yaml.lines[1..].join)
diff --git a/pages/docs/webdev.md b/pages/docs/webdev.md
index a8c88d5a7..1f2fb9222 100644
--- a/pages/docs/webdev.md
+++ b/pages/docs/webdev.md
@@ -15,26 +15,39 @@ You can always click the edit button to make small edits to the website source,
 
 #### Installing Ruby
 
-Visit [this page](https://jekyllrb.com/docs/installation/) for information about installing Ruby if your current version is too old; the instructions there form the basis for what you see here, and come in variants for all major operating systems.
-You should have Ruby 2.6+ for Jekyll; 3.1 recommended and used in CI. You can use rbenv to manage multiple ruby versions. On macOS with homebrew, you'll want:
+Visit [this page](https://jekyllrb.com/docs/installation/) for information
+about installing Ruby if your current version is too old; the instructions
+there form the basis for what you see here, and come in variants for all major
+operating systems.  You should have Ruby 2.6+ for Jekyll; 3.1+ recommended and
+used in CI. You can use rbenv to manage multiple ruby versions. On macOS with
+homebrew, you'll want:
 
 ```bash
 brew install rbenv
 ```
 
-You'll need to run `rbenv init` and follow the instructions for your current shell. After you've installed rbenv on your system, use:
+You'll need to run:
 
 ```bash
-rbenv install 3.1.2
+rbenv init
 ```
 
-to get a current version of ruby. Then, inside the main iris-hep website directory, run:
+and **then follow the instructions printed for your current shell**. After you've installed rbenv on your system, use:
 
 ```bash
-rbenv local 3.1.2
+rbenv install 3.2.2
 ```
 
-This will run the Ruby you just built whenever you enter this directory. You'll want to install bundler too:
+to get a current version of Ruby downloaded and built for your system. Then,
+inside the main iris-hep website directory, run:
+
+```bash
+rbenv local 3.2.2
+```
+
+This will add a file (`.ruby-version`, if you are curious) to your local
+directory that rbenv's shell integration will enable whenever you enter this
+directory. You'll want to install bundler too:
 
 ```bash
 gem install bundler
@@ -76,7 +89,7 @@ If you want to also perform the full link checking without exclusions, you can r
 bundle exec rake checkall
 ```
 
-If you are not familiar with it, `rake` is short for "Ruby make". The `clean` and `clobber` targets are available (the later removes the Inspire-HEP cache as well). You can also run `bundle exec jekyll ...` directly.
+If you are not familiar with it, `rake` is short for "Ruby make". The `clean` and `clobber` targets are available (the later removes the Inspire-HEP cache as well). You can see all available tasks with `bundle exec rake --tasks`. You can also run `bundle exec jekyll ...` directly.
 
 ### Using `pixi`
 
@@ -130,6 +143,20 @@ cat assets/js/myfile.js | openssl dgst -sha384 -binary | openssl base64 -A
 
 Run the site locally and verify no warnings appear in your terminal. Also turn on your browser's debugger and make sure no warnings are emitted.
 
+### Updating Ruby files
+
+If you edit Ruby files, you should run `rubocop` to verify:
+
+```bash
+bundle exec rake rubocop
+```
+
+If it suggests changes, you can often apply them automatically:
+
+```bash
+bundle exec rake rubocop:auto_correct
+```
+
 ### Styles
 
 Most style changes should be set in `assets/css/style.scss`. Some basic changes, like color variables, are set in the `_sass` directory. Please remember to consider multiple screen widths, printing (for relevant pages), and dark mode when changing or adding styles. You can see the defined colors [here](/docs/logos).