diff --git a/Gemfile b/Gemfile
index 0835532..c2bed45 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,7 +1,7 @@
 source "https://rubygems.org/"
 
 # Only needed for examples
-gem "thin-attach_socket"
+#gem "thin-attach_socket"
 
 # Specify your gem's dependencies in einhorn.gemspec
 gemspec
diff --git a/einhorn.gemspec b/einhorn.gemspec
index 8ca9ccd..6e3a32f 100644
--- a/einhorn.gemspec
+++ b/einhorn.gemspec
@@ -22,8 +22,8 @@ Gem::Specification.new do |gem|
     "changelog_uri" => "https://github.com/contribsys/einhorn/blob/main/Changes.md"
   }
 
-  gem.add_development_dependency "rake"
-  gem.add_development_dependency "minitest"
-  gem.add_development_dependency "mocha"
-  gem.add_development_dependency "subprocess"
+  gem.add_development_dependency "rake", "~> 13"
+  gem.add_development_dependency "minitest", "~> 5"
+  gem.add_development_dependency "mocha", "~> 1"
+  gem.add_development_dependency "subprocess", "~> 1"
 end