diff --git a/cf-uaa-lib.gemspec b/cf-uaa-lib.gemspec
index 51a7e9b..5211172 100644
--- a/cf-uaa-lib.gemspec
+++ b/cf-uaa-lib.gemspec
@@ -42,6 +42,7 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'simplecov-rcov', '~> 0.3.0'
   s.add_development_dependency 'ci_reporter', '>= 1.9.2', '~> 2.0'
   s.add_development_dependency 'json_pure', '~>2.7'
+  s.add_development_dependency 'json_pure', '>= 1.8.1', '~> 2.5'
   s.add_development_dependency 'ci_reporter_rspec', '~> 1.0'
 
 end