diff --git a/Gemfile b/Gemfile
index 16217ec..8ff07ec 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,5 @@
 source 'http://rubygems.org'
-gem 'activeresource', "3.0.9"
+gem 'activeresource', "5.1.1"
 gem 'prawn'
 gem 'thor'
 gem "pivotal_to_pdf-formatters", ">=0.0.4"
diff --git a/Gemfile.lock b/Gemfile.lock
index 21b89f9..bb768f9 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,17 +1,28 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    activemodel (3.0.9)
-      activesupport (= 3.0.9)
-      builder (~> 2.1.2)
-      i18n (~> 0.5.0)
-    activeresource (3.0.9)
-      activemodel (= 3.0.9)
-      activesupport (= 3.0.9)
-    activesupport (3.0.9)
-    builder (2.1.2)
+    activemodel (6.0.3.1)
+      activesupport (= 6.0.3.1)
+    activemodel-serializers-xml (1.0.2)
+      activemodel (> 5.x)
+      activesupport (> 5.x)
+      builder (~> 3.1)
+    activeresource (5.1.1)
+      activemodel (>= 5.0, < 7)
+      activemodel-serializers-xml (~> 1.0)
+      activesupport (>= 5.0, < 7)
+    activesupport (6.0.3.1)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
+      i18n (>= 0.7, < 2)
+      minitest (~> 5.1)
+      tzinfo (~> 1.1)
+      zeitwerk (~> 2.2, >= 2.2.2)
+    builder (3.2.4)
+    concurrent-ruby (1.1.6)
     diff-lcs (1.2.5)
-    i18n (0.5.4)
+    i18n (1.8.2)
+      concurrent-ruby (~> 1.0)
+    minitest (5.14.1)
     pdf-core (0.5.1)
     pivotal_to_pdf-formatters (0.2.1.1)
       rainbow
@@ -34,13 +45,17 @@ GEM
       rspec-support (~> 3.2.0)
     rspec-support (3.2.2)
     thor (0.19.1)
+    thread_safe (0.3.6)
     ttfunk (1.4.0)
+    tzinfo (1.2.7)
+      thread_safe (~> 0.1)
+    zeitwerk (2.3.0)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  activeresource (= 3.0.9)
+  activeresource (= 5.1.1)
   pivotal_to_pdf-formatters (>= 0.0.4)
   prawn
   rake
diff --git a/pivotal_to_pdf.gemspec b/pivotal_to_pdf.gemspec
index 7dcf605..7c57319 100644
--- a/pivotal_to_pdf.gemspec
+++ b/pivotal_to_pdf.gemspec
@@ -17,7 +17,7 @@ Gem::Specification.new do |s|
   s.require_paths = ["lib"]
   s.author         = "Yi Wen"
   s.add_runtime_dependency(%q<pivotal_to_pdf-formatters>, ">= 0.0.4")
-  s.add_runtime_dependency(%q<activeresource>, "3.0.9")
+  s.add_runtime_dependency(%q<activeresource>, "5.1.1")
   s.add_runtime_dependency(%q<prawn>, "0.12.0")
   s.add_runtime_dependency(%q<thor>, ">= 0")
   s.add_development_dependency(%q<rspec>)