diff --git a/Gemfile b/Gemfile
index e08d61455ce3..c987c3239b44 100644
--- a/Gemfile
+++ b/Gemfile
@@ -3,23 +3,25 @@ source 'https://rubygems.org'
 ruby '> 2.5.0'
 
 group :development do
-  gem 'rake', '13.0.1'
-  gem 'jekyll', '4.1.1'
+  gem 'rake', '13.0.6'
+  gem 'jekyll', '4.2.1'
   gem 'compass', '1.0.3'
   gem 'sass-globbing', '1.1.5'
   gem 'stringex', '2.8.5'
+  # > 2.1.0 causes slowdowns https://github.com/sass/sassc-ruby/issues/189
+  gem 'sassc', '2.4.0'
 end
 
 group :jekyll_plugins do
   gem 'jekyll-paginate', '1.1.0'
-  gem 'jekyll-redirect-from', '0.16.0'
   gem 'jekyll-sitemap', '1.4.0'
   gem 'jekyll-time-to-read', '0.1.2'
   gem 'jekyll-commonmark', '1.3.1'
+  gem 'jekyll-toc', '0.17.1'
 end
 
 gem 'sinatra', '2.1.0'
-gem 'nokogiri', '1.10.10'
+gem 'nokogiri', '1.12.5'
 
 # Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
 # and associated library
diff --git a/Gemfile.lock b/Gemfile.lock
index 9e126d48eb04..d001c62fc2f6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,11 +1,11 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.7.0)
+    addressable (2.8.0)
       public_suffix (>= 2.0.2, < 5.0)
-    chunky_png (1.3.12)
+    chunky_png (1.4.0)
     colorator (1.1.0)
-    commonmarker (0.21.0)
+    commonmarker (0.21.2)
       ruby-enum (~> 0.5)
     compass (1.0.3)
       chunky_png (~> 1.2)
@@ -19,79 +19,82 @@ GEM
       sass (>= 3.3.0, < 3.5)
     compass-import-once (1.0.5)
       sass (>= 3.2, < 3.5)
-    concurrent-ruby (1.1.7)
+    concurrent-ruby (1.1.9)
     em-websocket (0.5.2)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0.6.0)
     eventmachine (1.2.7)
     eventmachine (1.2.7-x64-mingw32)
-    ffi (1.13.1)
-    ffi (1.13.1-x64-mingw32)
+    ffi (1.15.4)
+    ffi (1.15.4-x64-mingw32)
     forwardable-extended (2.6.0)
     http_parser.rb (0.6.0)
-    i18n (1.8.5)
+    i18n (1.8.10)
       concurrent-ruby (~> 1.0)
-    jekyll (4.1.1)
+    jekyll (4.2.1)
       addressable (~> 2.4)
       colorator (~> 1.0)
       em-websocket (~> 0.5)
       i18n (~> 1.0)
       jekyll-sass-converter (~> 2.0)
       jekyll-watch (~> 2.0)
-      kramdown (~> 2.1)
+      kramdown (~> 2.3)
       kramdown-parser-gfm (~> 1.0)
       liquid (~> 4.0)
       mercenary (~> 0.4.0)
       pathutil (~> 0.9)
       rouge (~> 3.0)
       safe_yaml (~> 1.0)
-      terminal-table (~> 1.8)
+      terminal-table (~> 2.0)
     jekyll-commonmark (1.3.1)
       commonmarker (~> 0.14)
       jekyll (>= 3.7, < 5.0)
     jekyll-paginate (1.1.0)
-    jekyll-redirect-from (0.16.0)
-      jekyll (>= 3.3, < 5.0)
     jekyll-sass-converter (2.1.0)
       sassc (> 2.0.1, < 3.0)
     jekyll-sitemap (1.4.0)
       jekyll (>= 3.7, < 5.0)
     jekyll-time-to-read (0.1.2)
       jekyll
+    jekyll-toc (0.17.1)
+      jekyll (>= 3.9)
+      nokogiri (~> 1.11)
     jekyll-watch (2.2.1)
       listen (~> 3.0)
-    kramdown (2.3.0)
+    kramdown (2.3.1)
       rexml
     kramdown-parser-gfm (1.1.0)
       kramdown (~> 2.0)
     liquid (4.0.3)
-    listen (3.2.1)
+    listen (3.7.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
     mercenary (0.4.0)
-    mini_portile2 (2.4.0)
+    mini_portile2 (2.6.1)
     multi_json (1.15.0)
     mustermann (1.1.1)
       ruby2_keywords (~> 0.0.1)
-    nokogiri (1.10.10)
-      mini_portile2 (~> 2.4.0)
-    nokogiri (1.10.10-x64-mingw32)
-      mini_portile2 (~> 2.4.0)
+    nokogiri (1.12.5)
+      mini_portile2 (~> 2.6.1)
+      racc (~> 1.4)
+    nokogiri (1.12.5-x64-mingw32)
+      racc (~> 1.4)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     public_suffix (4.0.6)
+    racc (1.6.0)
     rack (2.2.3)
     rack-protection (2.1.0)
       rack
-    rake (13.0.1)
-    rb-fsevent (0.10.4)
+    rake (13.0.6)
+    rb-fsevent (0.11.0)
     rb-inotify (0.10.1)
       ffi (~> 1.0)
-    rexml (3.2.4)
-    rouge (3.23.0)
-    ruby-enum (0.8.0)
+    rexml (3.2.5)
+    rouge (3.26.1)
+    ruby-enum (0.9.0)
       i18n
-    ruby2_keywords (0.0.2)
+    ruby2_keywords (0.0.5)
     safe_yaml (1.0.5)
     sass (3.4.25)
     sass-globbing (1.1.5)
@@ -106,14 +109,14 @@ GEM
       rack-protection (= 2.1.0)
       tilt (~> 2.0)
     stringex (2.8.5)
-    terminal-table (1.8.0)
+    terminal-table (2.0.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     tilt (2.0.10)
-    tzinfo (2.0.2)
+    tzinfo (2.0.4)
       concurrent-ruby (~> 1.0)
-    tzinfo-data (1.2020.1)
+    tzinfo-data (1.2021.5)
       tzinfo (>= 1.0.0)
-    unicode-display_width (1.7.0)
+    unicode-display_width (1.8.0)
 
 PLATFORMS
   ruby
@@ -121,15 +124,16 @@ PLATFORMS
 
 DEPENDENCIES
   compass (= 1.0.3)
-  jekyll (= 4.1.1)
+  jekyll (= 4.2.1)
   jekyll-commonmark (= 1.3.1)
   jekyll-paginate (= 1.1.0)
-  jekyll-redirect-from (= 0.16.0)
   jekyll-sitemap (= 1.4.0)
   jekyll-time-to-read (= 0.1.2)
-  nokogiri (= 1.10.10)
-  rake (= 13.0.1)
+  jekyll-toc (= 0.17.1)
+  nokogiri (= 1.12.5)
+  rake (= 13.0.6)
   sass-globbing (= 1.1.5)
+  sassc (= 2.4.0)
   sinatra (= 2.1.0)
   stringex (= 2.8.5)
   tzinfo (~> 2.0)
@@ -139,4 +143,4 @@ RUBY VERSION
    ruby 2.6.2p47
 
 BUNDLED WITH
-   2.0.1
+   2.2.28