diff --git a/Gemfile b/Gemfile
index bd0ef75..9517c46 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,7 +4,7 @@ source 'https://rubygems.org'
 
 gem 'rake'
 gem 'mime-types'
-gem 'nanoc', '~> 3.0'
+gem 'nanoc', '~> 4.0'
 gem 'bitly'
 gem 'haml'
 gem 'sass'
diff --git a/Gemfile.lock b/Gemfile.lock
index ef05a74..5f5e6b9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,6 +1,8 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    addressable (2.5.2)
+      public_suffix (>= 2.0.2, < 4.0)
     adsf (1.4.0)
       rack (>= 1.0.0, < 3.0.0)
     bitly (1.1.0)
@@ -10,28 +12,38 @@ GEM
     builder (3.2.3)
     coderay (1.1.2)
     colored (1.2)
-    cri (2.9.1)
+    concurrent-ruby (1.0.5)
+    cri (2.13.0)
       colored (~> 1.2)
+    ddmemoize (1.0.0)
+      ddmetrics (~> 1.0)
+      ref (~> 2.0)
+    ddmetrics (1.0.1)
+    ddplugin (1.0.2)
     faraday (0.12.2)
       multipart-post (>= 1.2, < 3)
-    ffi (1.9.18)
+    ffi (1.9.25)
     formatador (0.2.5)
     fssm (0.2.10)
-    guard (2.14.1)
+    guard (2.14.2)
       formatador (>= 0.2.4)
       listen (>= 2.7, < 4.0)
-      lumberjack (~> 1.0)
+      lumberjack (>= 1.0.12, < 2.0)
       nenv (~> 0.1)
       notiffany (~> 0.0)
       pry (>= 0.9.12)
       shellany (~> 0.0)
       thor (>= 0.18.1)
-    guard-nanoc (1.0.3)
+    guard-compat (1.2.1)
+    guard-nanoc (2.1.3)
       guard (~> 2.8)
-      nanoc (~> 3.6)
+      guard-compat (~> 1.0)
+      nanoc (>= 4.3.8, < 5.0)
     haml (5.0.3)
       temple (>= 0.8.0)
       tilt
+    hamster (3.0.0)
+      concurrent-ruby (~> 1.0)
     httparty (0.15.6)
       multi_xml (>= 0.5.2)
     jwt (1.5.6)
@@ -39,7 +51,7 @@ GEM
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
       ruby_dep (~> 1.2)
-    lumberjack (1.0.12)
+    lumberjack (1.0.13)
     method_source (0.9.0)
     mime-types (3.1)
       mime-types-data (~> 3.2015)
@@ -48,8 +60,17 @@ GEM
     multi_json (1.12.2)
     multi_xml (0.6.0)
     multipart-post (2.0.0)
-    nanoc (3.8.0)
-      cri (~> 2.3)
+    nanoc (4.9.3)
+      addressable (~> 2.5)
+      cri (~> 2.8)
+      ddmemoize (~> 1.0)
+      ddmetrics (~> 1.0)
+      ddplugin (~> 1.0)
+      hamster (~> 3.0)
+      parallel (~> 1.12)
+      ref (~> 2.0)
+      slow_enumerator_tools (~> 1.0)
+      tomlrb (~> 1.2)
     nenv (0.3.0)
     nokogiri (1.8.1)
       mini_portile2 (~> 2.3.0)
@@ -62,17 +83,18 @@ GEM
       multi_json (~> 1.3)
       multi_xml (~> 0.5)
       rack (>= 1.2, < 3)
-    pry (0.11.1)
+    parallel (1.12.1)
+    pry (0.11.3)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
+    public_suffix (3.0.3)
     rack (2.0.3)
     rake (12.1.0)
-    rb-fsevent (0.10.2)
+    rb-fsevent (0.10.3)
     rb-inotify (0.9.10)
       ffi (>= 0.5.0, < 2)
-    rb-kqueue (0.2.5)
-      ffi (>= 0.5.0)
     rdiscount (2.2.0.1)
+    ref (2.0.0)
     ruby_dep (1.5.0)
     rubypants (0.6.0)
     sass (3.5.1)
@@ -81,10 +103,12 @@ GEM
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
     shellany (0.0.1)
+    slow_enumerator_tools (1.1.0)
     systemu (2.6.5)
     temple (0.8.0)
     thor (0.20.0)
     tilt (2.0.8)
+    tomlrb (1.2.7)
 
 PLATFORMS
   ruby
@@ -98,10 +122,9 @@ DEPENDENCIES
   haml
   listen
   mime-types
-  nanoc (~> 3.0)
+  nanoc (~> 4.0)
   nokogiri
   rake
-  rb-kqueue (>= 0.2)
   rdiscount
   rubypants
   sass
diff --git a/Rakefile b/Rakefile
index f484d24..1f926d6 100644
--- a/Rakefile
+++ b/Rakefile
@@ -1 +1 @@
-require 'nanoc3/tasks'
\ No newline at end of file
+require 'nanoc/tasks'
diff --git a/config.yaml b/config.yaml
index 13a233e..4a8fc40 100644
--- a/config.yaml
+++ b/config.yaml
@@ -24,11 +24,13 @@ enable_output_diff: false
 # hashes; each array element represents a single data source. By default,
 # there is only a single data source that reads data from the “content/” and
 # “layout/” directories in the site directory.
+string_pattern_type: legacy
 data_sources:
   -
     # The type is the identifier of the data source. By default, this will be
     # `filesystem_unified`.
     type: filesystem_unified
+    identifier_type: legacy
 
     # The path where items should be mounted (comparable to mount points in
     # Unix-like systems). This is “/” by default, meaning that items will have
diff --git a/content/robots.txt b/content/robots.txt
index 7c131a2..fd8ea93 100644
--- a/content/robots.txt
+++ b/content/robots.txt
@@ -1,3 +1,3 @@
 User-Agent: *
 Disallow: 
-Sitemap: <%= @site.config[:base_url] %>/sitemap.xml
+Sitemap: <%= @config[:base_url] %>/sitemap.xml
diff --git a/layouts/_article.html b/layouts/_article.html
index 88b232c..a50f3ca 100644
--- a/layouts/_article.html
+++ b/layouts/_article.html
@@ -6,7 +6,7 @@
     <span class="year"><%= post_date.year %></span>
   </abbr>
   <p>
-    <strong><a href="<%= @article.reps.first.path %>"><%=h @article[:title] %></a></strong>
+    <strong><a href="<%= @article.reps[:default].path %>"><%=h @article[:title] %></a></strong>
     <%=h @article[:extra] %>
   </p>
 </li>
diff --git a/layouts/_listing.html b/layouts/_listing.html
index b7ab956..887c214 100644
--- a/layouts/_listing.html
+++ b/layouts/_listing.html
@@ -28,7 +28,7 @@
             <span class="year"><%= post_date.year %></span>
           </abbr>
           <p>
-            <strong><a href="<%= article.reps.first.path %>"><%= article[:title] %></a></strong>
+            <strong><a href="<%= article.reps[:default].path %>"><%= article[:title] %></a></strong>
             A one sentence summary of this post would go here this one is longer then the other one.
           </p>
         </li>
@@ -63,7 +63,7 @@
             <span class="year"><%= post_date.year %></span>
           </abbr>
           <p>
-            <strong><a href="<%= article.reps.first.path %>"><%= article[:title] %></a></strong>
+            <strong><a href="<%= article.reps[:default].path %>"><%= article[:title] %></a></strong>
             A one sentence summary of this post would go here.</p>
         </li>
       <% end %>
diff --git a/layouts/articles.html b/layouts/articles.html
index c876c66..73d3d99 100644
--- a/layouts/articles.html
+++ b/layouts/articles.html
@@ -30,7 +30,7 @@
         else
           feed = '/feed/'
         end
-        active = (@item.identifier.sub(%r{page/$}, '') == path)
+        active = (@item.identifier.to_s.sub(%r{page/$}, '') == path)
       %>
       <li>
         <a href="<%= feed %>"><img class="feed-icon" src="/images/feed-icon.svg" width="12" height="12" alt="Feed Icon" /></a>
diff --git a/layouts/default.html b/layouts/default.html
index 495dd1f..6c4d783 100644
--- a/layouts/default.html
+++ b/layouts/default.html
@@ -12,7 +12,7 @@
 <body<%= %Q( class="#{@item[:body_class]}") if @item[:body_class] %>>
   <%= render '_header' %>
   <div id="content">
-    <h1><a href="<%= @item.reps.first.path %>"><%=h @item[:title] %></a></h1>
+    <h1><a href="<%= @item.reps[:default].path %>"><%=h @item[:title] %></a></h1>
     <%= yield %>
   </div>
   <%= render '_footer' %>
diff --git a/layouts/topphoto.html b/layouts/topphoto.html
index 20e3ee9..49b76a1 100644
--- a/layouts/topphoto.html
+++ b/layouts/topphoto.html
@@ -15,7 +15,7 @@
   <img src="<%= @item[:photo] %>" alt="<%= @item[:photo_alt] %>" class="cover-photo" />
 
   <div id="content">
-    <h1><a href="<%= @item.reps.first.path %>"><%=h @item[:title] %></a></h1>
+    <h1><a href="<%= @item.reps[:default].path %>"><%=h @item[:title] %></a></h1>
     <%= yield %>
   </div>
   <%= render '_footer' %>
diff --git a/layouts/weather.html b/layouts/weather.html
index c8994d8..71a5f80 100644
--- a/layouts/weather.html
+++ b/layouts/weather.html
@@ -11,7 +11,7 @@
 <body class="weather">
   <%= render '_header' %>
   <div id="content">
-    <h1><a href="<%= @item.reps.first.path %>"><%=h @item[:title] %></a></h1>
+    <h1><a href="<%= @item.reps[:default].path %>"><%=h @item[:title] %></a></h1>
     <%= yield %>
   </div>
   <%= render '_footer' %>
diff --git a/lib/default.rb b/lib/default.rb
index ab4f4f4..1a3d129 100644
--- a/lib/default.rb
+++ b/lib/default.rb
@@ -3,8 +3,8 @@
 
 require 'json'
 
-include Nanoc3::Helpers::Rendering
-include Nanoc3::Helpers::Blogging
-include Nanoc3::Helpers::XMLSitemap
-include Nanoc3::Helpers::HTMLEscape
+include Nanoc::Helpers::Rendering
+include Nanoc::Helpers::Blogging
+include Nanoc::Helpers::XMLSitemap
+include Nanoc::Helpers::HTMLEscape
 include WezM::Helpers::Articles
diff --git a/script/bitly b/script/bitly
index 98759ed..d4ed6a4 100755
--- a/script/bitly
+++ b/script/bitly
@@ -3,13 +3,13 @@
 require 'pathname'
 $:.unshift (Pathname(__FILE__).parent.parent + 'lib').to_s
 
-require 'nanoc3'
+require 'nanoc'
 require 'articles'
 require 'bitly'
 
-include Nanoc3::Helpers::Blogging
+include Nanoc::Helpers::Blogging
 
-site = Nanoc3::Site.new(Pathname(__FILE__).parent.parent.to_s)
+site = Nanoc::Site.new(Pathname(__FILE__).parent.parent.to_s)
 
 Bitly.use_api_version_3
 bitly = Bitly.new('wezm', 'R_f2bfdace56c886671086eb0c8acb9ce7')
diff --git a/script/importer/wordpress.rb b/script/importer/wordpress.rb
index 6577a70..5860e62 100644
--- a/script/importer/wordpress.rb
+++ b/script/importer/wordpress.rb
@@ -1,5 +1,5 @@
 require 'nokogiri'
-require 'nanoc3'
+require 'nanoc'
 require 'uri'
 
 module Importer
@@ -9,7 +9,7 @@ module Importer
     def initialize(wordpress_export_path, nanoc_site_path, rewrite_map_path)
       @export_file = File.open(wordpress_export_path)
       @export = Nokogiri::XML(@export_file)
-      @site = Nanoc3::Site.new(nanoc_site_path)
+      @site = Nanoc::Site.new(nanoc_site_path)
       @rewrite_map = []
       @rewrite_map_path = rewrite_map_path