diff --git a/rest-client.gemspec b/rest-client.gemspec
index 513b8de..9cba774 100644
--- a/rest-client.gemspec
+++ b/rest-client.gemspec
@@ -18,10 +18,10 @@ Gem::Specification.new do |s|
 
   s.add_development_dependency('webmock', '~> 1.4')
   s.add_development_dependency('rspec', '~> 2.4')
-  s.add_development_dependency('pry')
-  s.add_development_dependency('pry-doc')
+  s.add_development_dependency('pry', '~> 0')
+  s.add_development_dependency('pry-doc', '~> 0')
   s.add_development_dependency('rdoc', '>= 2.4.2', '< 5.0')
-  s.add_development_dependency('rubocop')
+  s.add_development_dependency('rubocop', '~> 0')
 
   s.add_dependency('http-cookie', '>= 1.0.2', '< 2.0')
   s.add_dependency('mime-types', '>= 1.16', '< 3.0')