diff --git a/Gemfile b/Gemfile
index 61c8de3c..f5734954 100644
--- a/Gemfile
+++ b/Gemfile
@@ -53,10 +53,8 @@ gem 'hiredis'
 gem 'image_processing'
 gem 'icalendar'
 gem 'inline_svg'
-gem 'jekyll', git: 'https://0xacab.org/sutty/jekyll/jekyll.git',
-              branch: 'master'
-gem 'jekyll-data', require: 'jekyll-data',
-                   git: 'https://0xacab.org/sutty/jekyll/jekyll-data.git'
+gem 'jekyll', '~> 4.2'
+gem 'jekyll-data', source: 'https://gems.sutty.nl'
 gem 'jekyll-commonmark'
 gem 'jekyll-images'
 gem 'jekyll-include-cache'
diff --git a/Gemfile.lock b/Gemfile.lock
index ca1d309a..ac0d7755 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,31 +1,3 @@
-GIT
-  remote: https://0xacab.org/sutty/jekyll/jekyll-data.git
-  revision: 1ad9c175be6bbb31ae6d19cbb8dde18828af90d9
-  specs:
-    jekyll-data (1.1.0)
-      jekyll (>= 3.3, < 5.0.0)
-
-GIT
-  remote: https://0xacab.org/sutty/jekyll/jekyll.git
-  revision: 49d4f5c0eb3738bb312ba5f40fa3f3734e1a1cca
-  branch: master
-  specs:
-    jekyll (4.1.1)
-      addressable (~> 2.4)
-      colorator (~> 1.0)
-      em-websocket (~> 0.5)
-      i18n (~> 1.0)
-      jekyll-sass-converter (~> 2.0)
-      jekyll-watch (~> 2.0)
-      kramdown (~> 2.3)
-      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)
-
 GIT
   remote: https://0xacab.org/sutty/yaml_db.git
   revision: 40e44c29ce4290dfe4013ff4fce1be5a936fedf4
@@ -36,6 +8,7 @@ GIT
 
 GEM
   remote: https://rubygems.org/
+  remote: https://gems.sutty.nl/
   specs:
     actioncable (6.1.0)
       actionpack (= 6.1.0)
@@ -122,7 +95,7 @@ GEM
       autoprefixer-rails (>= 9.1.0)
       popper_js (>= 1.14.3, < 2)
       sassc-rails (>= 2.0.0)
-    brakeman (4.10.0)
+    brakeman (4.10.1)
     builder (3.2.4)
     capybara (2.18.0)
       addressable
@@ -217,7 +190,7 @@ GEM
       rainbow
       rubocop (>= 0.50.0)
       sysexits (~> 1.1)
-    hamlit (2.13.0)
+    hamlit (2.13.2)
       temple (>= 0.8.2)
       thor
       tilt
@@ -243,9 +216,26 @@ GEM
       nokogiri (>= 1.6)
     jbuilder (2.10.1)
       activesupport (>= 5.0.0)
+    jekyll (4.2.0)
+      addressable (~> 2.4)
+      colorator (~> 1.0)
+      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 (~> 0.4.0)
+      pathutil (~> 0.9)
+      rouge (~> 3.0)
+      safe_yaml (~> 1.0)
+      terminal-table (~> 2.0)
     jekyll-commonmark (1.3.1)
       commonmarker (~> 0.14)
       jekyll (>= 3.7, < 5.0)
+    jekyll-data (1.1.2)
+      jekyll (>= 3.3, < 5.0.0)
     jekyll-feed (0.15.1)
       jekyll (>= 3.7, < 5.0)
     jekyll-images (0.2.7)
@@ -325,13 +315,14 @@ GEM
       mini_portile2 (~> 2.4.0)
     orm_adapter (0.5.0)
     parallel (1.20.1)
-    parser (2.7.2.0)
+    parser (3.0.0.0)
       ast (~> 2.4.1)
     pathutil (0.16.2)
       forwardable-extended (~> 2.6)
     pg (1.2.3)
     popper_js (1.16.0)
-    prometheus_exporter (0.6.0)
+    prometheus_exporter (0.7.0)
+      webrick
     pry (0.13.1)
       coderay (~> 1.1)
       method_source (~> 1.0)
@@ -343,7 +334,7 @@ GEM
     rack (2.2.3)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
-    rack-mini-profiler (2.2.1)
+    rack-mini-profiler (2.3.0)
       rack (>= 1.2.0)
     rack-proxy (0.6.5)
       rack
@@ -430,7 +421,7 @@ GEM
       redis-store (>= 1.2, < 2)
     redis-store (1.9.0)
       redis (>= 4, < 5)
-    regexp_parser (2.0.1)
+    regexp_parser (2.0.3)
     request_store (1.5.0)
       rack (>= 1.4)
     responders (3.0.1)
@@ -438,7 +429,7 @@ GEM
       railties (>= 5.0)
     rexml (3.2.4)
     rouge (3.26.0)
-    rubocop (1.6.1)
+    rubocop (1.7.0)
       parallel (~> 1.10)
       parser (>= 2.7.1.5)
       rainbow (>= 2.2.2, < 4.0)
@@ -533,7 +524,7 @@ GEM
     symbol-fstring (1.0.0)
     sysexits (1.2.0)
     temple (0.8.2)
-    terminal-table (1.8.0)
+    terminal-table (2.0.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     thor (1.0.1)
     tilt (2.0.10)
@@ -564,6 +555,7 @@ GEM
       rack-proxy (>= 0.6.1)
       railties (>= 5.2)
       semantic_range (>= 2.3.0)
+    webrick (1.7.0)
     websocket-driver (0.7.3)
       websocket-extensions (>= 0.1.0)
     websocket-extensions (0.1.5)
@@ -604,7 +596,7 @@ DEPENDENCIES
   image_processing
   inline_svg
   jbuilder (~> 2.5)
-  jekyll!
+  jekyll (~> 4.2)
   jekyll-commonmark
   jekyll-data!
   jekyll-images
diff --git a/config/initializers/core_extensions.rb b/config/initializers/core_extensions.rb
index 50370e07..e37b2be4 100644
--- a/config/initializers/core_extensions.rb
+++ b/config/initializers/core_extensions.rb
@@ -55,4 +55,14 @@ module Jekyll
     alias_method :read!, :read
     def read; end
   end
+
+  # https://github.com/jekyll/jekyll/pull/8425
+  Utils.class_eval do
+    def parse_date(input, msg = 'Input could not be parsed.')
+      @parse_date_cache ||= {}
+      @parse_date_cache[input] ||= Time.parse(input).localtime
+    rescue ArgumentError
+      raise Errors::InvalidDateError, "Invalid date '#{input}': #{msg}"
+    end
+  end
 end