diff --git a/Gemfile.lock b/Gemfile.lock
index 1fa8b86..5c3e108 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -7,7 +7,12 @@ PATH
 GEM
   remote: http://rubygems.org/
   specs:
-    activesupport (3.0.3)
+    activesupport (6.0.0)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
+      minitest (~> 5.1)
+      tzinfo (~> 1.1)
+      zeitwerk (~> 2.1, >= 2.1.8)
     archive-tar-minitar (0.5.2)
     capybara (0.4.0)
       celerity (>= 0.7.9)
@@ -26,6 +31,7 @@ GEM
     compass (0.11.beta.2)
       chunky_png (~> 0.12.0)
       sass (>= 3.1.0.alpha.218)
+    concurrent-ruby (1.1.5)
     configuration (1.2.0)
     culerity (0.2.14)
     daemons (1.1.0)
@@ -43,7 +49,8 @@ GEM
       launchy (~> 0.3.7)
       text-format (= 1.0.0)
     highline (1.5.2)
-    i18n (0.5.0)
+    i18n (1.7.0)
+      concurrent-ruby (~> 1.0)
     infinity_test (1.0.2)
       notifiers (>= 1.1.0)
       watchr (>= 0.7)
@@ -63,6 +70,7 @@ GEM
     markup_validity (1.1.0)
       nokogiri (>= 1.3.1)
     mime-types (1.16)
+    minitest (5.12.2)
     mustache (0.12.0)
     nokogiri (1.4.4)
     notifiers (1.1.0)
@@ -127,19 +135,23 @@ GEM
       eventmachine (>= 0.12.6)
       rack (>= 1.0.0)
     thor (0.14.6)
+    thread_safe (0.3.6)
     tilt (1.2.1)
     tmail (1.2.7.1)
     treetop (1.4.9)
       polyglot (>= 0.3.1)
+    tzinfo (1.2.5)
+      thread_safe (~> 0.1)
     watchr (0.7)
     xpath (0.1.2)
       nokogiri (~> 1.3)
+    zeitwerk (2.2.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  activesupport (~> 3.0.3)
+  activesupport (~> 6.0.0)
   capybara
   compass (~> 0.11.beta.2)
   fuubar
diff --git a/moz_nav.gemspec b/moz_nav.gemspec
index 280bd26..c3e8864 100644
--- a/moz_nav.gemspec
+++ b/moz_nav.gemspec
@@ -23,7 +23,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'fuubar'
   s.add_development_dependency 'capybara'
   s.add_development_dependency 'markup_validity'
-  s.add_development_dependency 'activesupport', '~> 3.0.3'
+  s.add_development_dependency 'activesupport', '~> 6.0.0'
   s.add_development_dependency 'shotgun'
   s.add_development_dependency 'compass', '~> 0.11.beta.2'
   s.add_development_dependency 'oily_png'