diff --git a/Gemfile b/Gemfile
index 77761b1..79bdc46 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,17 +8,19 @@ source "https://rubygems.org"
 #
 # This will help ensure the proper Jekyll version is running.
 # Happy Jekylling!
-gem "jekyll", "~> 3.8.3"
+gem "jekyll", "~> 4.2.0"
 
 # Use this theme instead.
-gem "jekyll-theme-hydeout", "~> 3.4"
-
-# If you want to use GitHub Pages, remove the "gem "jekyll"" above and
-# uncomment the line below. To upgrade, run `bundle update github-pages`.
-# gem "github-pages", group: :jekyll_plugins
+gem "jekyll-theme-hydeout", "~> 4.2.0"
 
 # If you have any plugins, put them here!
 group :jekyll_plugins do
   gem "jekyll-admin"
   gem "jekyll-feed", "~> 0.6"
 end
+
+# Necessary for jekyll-admin to work (Webrick is missing in Ruby >= 3.0).
+gem "webrick"
+
+# Support GFM dialect of Markdown.
+gem "kramdown-parser-gfm"
diff --git a/Gemfile.lock b/Gemfile.lock
index bc14f51..9a398d2 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -10,7 +10,7 @@ GEM
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
     eventmachine (1.2.7)
-    faraday (1.9.3)
+    faraday (1.10.0)
       faraday-em_http (~> 1.0)
       faraday-em_synchrony (~> 1.0)
       faraday-excon (~> 1.1)
@@ -36,45 +36,50 @@ GEM
     ffi (1.15.5)
     forwardable-extended (2.6.0)
     http_parser.rb (0.8.0)
-    i18n (0.9.5)
+    i18n (1.10.0)
       concurrent-ruby (~> 1.0)
-    jekyll (3.8.7)
+    jekyll (4.2.2)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
-      i18n (~> 0.7)
-      jekyll-sass-converter (~> 1.0)
+      i18n (~> 1.0)
+      jekyll-sass-converter (~> 2.0)
       jekyll-watch (~> 2.0)
-      kramdown (~> 1.14)
+      kramdown (~> 2.3)
+      kramdown-parser-gfm (~> 1.0)
       liquid (~> 4.0)
-      mercenary (~> 0.3.3)
+      mercenary (~> 0.4.0)
       pathutil (~> 0.9)
-      rouge (>= 1.7, < 4)
+      rouge (~> 3.0)
       safe_yaml (~> 1.0)
+      terminal-table (~> 2.0)
     jekyll-admin (0.11.0)
       jekyll (>= 3.7, < 5.0)
       sinatra (~> 1.4)
       sinatra-contrib (~> 1.4)
-    jekyll-feed (0.16.0)
+    jekyll-feed (0.15.1)
       jekyll (>= 3.7, < 5.0)
     jekyll-gist (1.5.0)
       octokit (~> 4.2)
     jekyll-paginate (1.1.0)
-    jekyll-sass-converter (1.5.2)
-      sass (~> 3.4)
-    jekyll-theme-hydeout (3.7.1)
-      jekyll (~> 3.4)
+    jekyll-sass-converter (2.2.0)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-theme-hydeout (4.2.0)
+      jekyll (>= 3.6, < 5.0)
       jekyll-feed (~> 0.6)
       jekyll-gist (~> 1.4)
       jekyll-paginate (~> 1.1)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (1.17.0)
+    kramdown (2.3.1)
+      rexml
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
     liquid (4.0.3)
     listen (3.7.1)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
-    mercenary (0.3.6)
+    mercenary (0.4.0)
     multi_json (1.15.0)
     multipart-post (2.1.1)
     octokit (4.22.0)
@@ -88,17 +93,15 @@ GEM
       rack
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
-    rb-fsevent (0.11.0)
+    rb-fsevent (0.11.1)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rouge (3.27.0)
+    rexml (3.2.5)
+    rouge (3.28.0)
     ruby2_keywords (0.0.5)
     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)
+    sassc (2.4.0)
+      ffi (~> 1.9)
     sawyer (0.8.2)
       addressable (>= 2.3.5)
       faraday (> 0.8, < 2.0)
@@ -113,16 +116,22 @@ GEM
       rack-test
       sinatra (~> 1.4.0)
       tilt (>= 1.3, < 3)
+    terminal-table (2.0.0)
+      unicode-display_width (~> 1.1, >= 1.1.1)
     tilt (2.0.10)
+    unicode-display_width (1.8.0)
+    webrick (1.7.0)
 
 PLATFORMS
-  ruby
+  x86_64-linux
 
 DEPENDENCIES
-  jekyll (~> 3.8.3)
+  jekyll (~> 4.2.0)
   jekyll-admin
   jekyll-feed (~> 0.6)
-  jekyll-theme-hydeout (~> 3.4)
+  jekyll-theme-hydeout (~> 4.2.0)
+  kramdown-parser-gfm
+  webrick
 
 BUNDLED WITH
-   2.1.4
+   2.3.5