diff --git a/lib/fhir_models/bootstrap/json.rb b/lib/fhir_models/bootstrap/json.rb
index d156b26a..7a72cf0b 100644
--- a/lib/fhir_models/bootstrap/json.rb
+++ b/lib/fhir_models/bootstrap/json.rb
@@ -7,7 +7,7 @@ module Json
     #
 
     def to_json
-      JSON.pretty_unparse(to_hash)
+      JSON.pretty_generate(to_hash)
     end
 
     def self.from_json(json, namespace = FHIR)
diff --git a/lib/fhir_models/bootstrap/preprocess.rb b/lib/fhir_models/bootstrap/preprocess.rb
index 9939ec5b..8c599192 100644
--- a/lib/fhir_models/bootstrap/preprocess.rb
+++ b/lib/fhir_models/bootstrap/preprocess.rb
@@ -26,7 +26,7 @@ def self.pre_process_bundle(filename)
 
         # Output the post processed file
         f = File.open(filename, 'w:UTF-8')
-        f.write(JSON.pretty_unparse(hash))
+        f.write(JSON.pretty_generate(hash))
         f.close
         finish = File.size(filename)
         puts "  Removed #{(start - finish) / 1024} KB" if start != finish
@@ -131,7 +131,7 @@ def self.pre_process_json_example(filename)
 
         # Output the post processed file
         f = File.open(filename, 'w:UTF-8')
-        f.write(JSON.pretty_unparse(hash))
+        f.write(JSON.pretty_generate(hash))
         f.close
         finish = File.size(filename)
         puts "  Removed #{(start - finish) / 1024} KB" if start != finish
diff --git a/lib/fhir_models/fhir_ext/structure_definition_finding.rb b/lib/fhir_models/fhir_ext/structure_definition_finding.rb
index 9dbaf0c2..e256e8b3 100644
--- a/lib/fhir_models/fhir_ext/structure_definition_finding.rb
+++ b/lib/fhir_models/fhir_ext/structure_definition_finding.rb
@@ -16,7 +16,7 @@ def to_s
     end
 
     def to_json
-      JSON.pretty_unparse(as_json)
+      JSON.pretty_generate(as_json)
     end
 
     def from_json(json)
diff --git a/lib/fhir_models/tasks/tasks.rake b/lib/fhir_models/tasks/tasks.rake
index 42f28346..d2e4ca24 100644
--- a/lib/fhir_models/tasks/tasks.rake
+++ b/lib/fhir_models/tasks/tasks.rake
@@ -316,7 +316,7 @@ namespace :fhir do
 
       # Output the post processed file
       f = File.open(filename, 'w:UTF-8')
-      f.write(JSON.pretty_unparse(hash))
+      f.write(JSON.pretty_generate(hash))
       f.close
       finish = File.size(filename)
       puts "  Removed #{(start - finish) / 1024} KB" if start != finish
diff --git a/test/unit/json_validation_test.rb b/test/unit/json_validation_test.rb
index dbecc602..337b7d89 100644
--- a/test/unit/json_validation_test.rb
+++ b/test/unit/json_validation_test.rb
@@ -24,7 +24,7 @@ def run_json_validation_test(example_file, example_name)
     resource = FHIR::Json.from_json(input_json)
     errors = resource.validate
     unless errors.empty?
-      File.open("#{ERROR_DIR}/#{example_name}.err", 'w:UTF-8') { |file| file.write(JSON.pretty_unparse(errors)) }
+      File.open("#{ERROR_DIR}/#{example_name}.err", 'w:UTF-8') { |file| file.write(JSON.pretty_generate(errors)) }
       File.open("#{ERROR_DIR}/#{example_name}.json", 'w:UTF-8') { |file| file.write(input_json) }
     end
     assert errors.empty?, "Resource failed to validate: #{errors}"
diff --git a/test/unit/xml_validation_test.rb b/test/unit/xml_validation_test.rb
index e2928d97..b542f688 100644
--- a/test/unit/xml_validation_test.rb
+++ b/test/unit/xml_validation_test.rb
@@ -24,7 +24,7 @@ def run_xml_validation_test(example_file, example_name)
     resource = FHIR::Xml.from_xml(input_xml)
     errors = resource.validate
     unless errors.empty?
-      File.open("#{ERROR_DIR}/#{example_name}.err", 'w:UTF-8') { |file| file.write(JSON.pretty_unparse(errors)) }
+      File.open("#{ERROR_DIR}/#{example_name}.err", 'w:UTF-8') { |file| file.write(JSON.pretty_generate(errors)) }
       File.open("#{ERROR_DIR}/#{example_name}.xml", 'w:UTF-8') { |file| file.write(input_xml) }
     end
     assert errors.empty?, 'Resource failed to validate.'