diff --git a/Gemfile b/Gemfile
index 8731a78f..abeca8b1 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,5 +4,5 @@ gem 'rocco'
 gem 'tilt'
 gem 'rake'
 gem 'phantomjs'
-gem 'jekyll'
-gem 'jekyll-redirect-from'
+gem 'jekyll', '>= 3.6.2'
+gem 'jekyll-redirect-from', '>= 0.13.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index c78fa9f8..915bb726 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,66 +1,82 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    addressable (2.5.2)
-      public_suffix (>= 2.0.2, < 4.0)
+    addressable (2.8.0)
+      public_suffix (>= 2.0.2, < 5.0)
     colorator (1.1.0)
-    ffi (1.9.18)
+    concurrent-ruby (1.1.9)
+    em-websocket (0.5.2)
+      eventmachine (>= 0.12.9)
+      http_parser.rb (~> 0.6.0)
+    eventmachine (1.2.7)
+    ffi (1.15.3)
     forwardable-extended (2.6.0)
-    jekyll (3.6.2)
+    http_parser.rb (0.6.0)
+    i18n (1.8.10)
+      concurrent-ruby (~> 1.0)
+    jekyll (4.2.0)
       addressable (~> 2.4)
       colorator (~> 1.0)
-      jekyll-sass-converter (~> 1.0)
-      jekyll-watch (~> 1.1)
-      kramdown (~> 1.14)
+      em-websocket (~> 0.5)
+      i18n (~> 1.0)
+      jekyll-sass-converter (~> 2.0)
+      jekyll-watch (~> 2.0)
+      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, < 3)
+      rouge (~> 3.0)
       safe_yaml (~> 1.0)
-    jekyll-redirect-from (0.13.0)
-      jekyll (~> 3.3)
-    jekyll-sass-converter (1.5.0)
-      sass (~> 3.4)
-    jekyll-watch (1.5.0)
-      listen (~> 3.0, < 3.1)
-    kramdown (1.15.0)
-    liquid (4.0.0)
-    listen (3.0.8)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
-    mercenary (0.3.6)
+      terminal-table (~> 2.0)
+    jekyll-redirect-from (0.16.0)
+      jekyll (>= 3.3, < 5.0)
+    jekyll-sass-converter (2.1.0)
+      sassc (> 2.0.1, < 3.0)
+    jekyll-watch (2.2.1)
+      listen (~> 3.0)
+    kramdown (2.3.1)
+      rexml
+    kramdown-parser-gfm (1.1.0)
+      kramdown (~> 2.0)
+    liquid (4.0.3)
+    listen (3.5.1)
+      rb-fsevent (~> 0.10, >= 0.10.3)
+      rb-inotify (~> 0.9, >= 0.9.10)
+    mercenary (0.4.0)
     mustache (1.0.5)
-    pathutil (0.16.0)
+    pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     phantomjs (2.1.1.0)
-    public_suffix (3.0.0)
+    public_suffix (4.0.6)
     rake (12.2.1)
-    rb-fsevent (0.10.2)
-    rb-inotify (0.9.10)
-      ffi (>= 0.5.0, < 2)
+    rb-fsevent (0.11.0)
+    rb-inotify (0.10.1)
+      ffi (~> 1.0)
     redcarpet (3.4.0)
+    rexml (3.2.5)
     rocco (0.8.2)
       mustache
       redcarpet
-    rouge (2.2.1)
-    safe_yaml (1.0.4)
-    sass (3.5.3)
-      sass-listen (~> 4.0.0)
-    sass-listen (4.0.0)
-      rb-fsevent (~> 0.9, >= 0.9.4)
-      rb-inotify (~> 0.9, >= 0.9.7)
+    rouge (3.26.0)
+    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)
     tilt (2.0.8)
+    unicode-display_width (1.7.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  jekyll
-  jekyll-redirect-from
+  jekyll (>= 3.6.2)
+  jekyll-redirect-from (>= 0.13.0)
   phantomjs
   rake
   rocco
   tilt
 
 BUNDLED WITH
-   1.16.1
+   1.17.3