diff --git a/Gemfile b/Gemfile
index 601147d..3277ba5 100644
--- a/Gemfile
+++ b/Gemfile
@@ -5,6 +5,7 @@ gemspec
 gem "rspec"
 gem "byebug"
 gem "rails", "~> 7.1.0"
+gem "json", "< 3"
 gem "analyzer", git: "https://github.com/thoughtbot/analyzer.git"
 gem "multi_json"
 gem "rabl"
diff --git a/Gemfile.71 b/Gemfile.71
index 3606490..04b8610 100644
--- a/Gemfile.71
+++ b/Gemfile.71
@@ -4,4 +4,5 @@ gemspec
 gem "rspec"
 gem "byebug"
 gem "rails", "~> 7.1.0"
+gem "json", "< 3"
 gem "standard", group: [:development, :test]
diff --git a/Gemfile.80 b/Gemfile.80
index 235a6d2..270abc6 100644
--- a/Gemfile.80
+++ b/Gemfile.80
@@ -4,4 +4,5 @@ gemspec
 gem "rspec"
 gem "byebug"
 gem "rails", "~> 8.0.0"
+gem "json", "< 3"
 gem "standard", group: [:development, :test]
diff --git a/spec/props_template_spec.rb b/spec/props_template_spec.rb
index cb475b0..95e1e0b 100644
--- a/spec/props_template_spec.rb
+++ b/spec/props_template_spec.rb
@@ -98,7 +98,7 @@
       json.set! :foo, "bar"
       json.set! :foo, "cool"
 
-      attrs = JSON.parse(json.result!)
+      attrs = JSON.parse(json.result!, allow_duplicate_key: true)
 
       expect(attrs).to eql({
         "foo" => "cool"