diff --git a/aruba.gemspec b/aruba.gemspec
index a6e98ee4f..5016ef8ad 100644
--- a/aruba.gemspec
+++ b/aruba.gemspec
@@ -23,7 +23,7 @@ Gem::Specification.new do |spec|
     'source_code_uri' => 'https://github.com/cucumber/aruba'
   }
 
-  spec.add_runtime_dependency 'childprocess', '~> 3.0'
+  spec.add_runtime_dependency 'childprocess', ['>= 2.0', '< 5.0']
   spec.add_runtime_dependency 'contracts', '~> 0.16.0'
   spec.add_runtime_dependency 'cucumber', ['>= 2.4', '< 5.0']
   spec.add_runtime_dependency 'ffi', '~> 1.9'