diff --git a/amplitude-experiment.gemspec b/amplitude-experiment.gemspec
index 42a8b5a..18d27fc 100644
--- a/amplitude-experiment.gemspec
+++ b/amplitude-experiment.gemspec
@@ -18,7 +18,7 @@ Gem::Specification.new do |spec|
   spec.require_paths         = ['lib']
   spec.extra_rdoc_files      = ['README.md']
 
-  spec.add_dependency 'concurrent-ruby', '~> 1.2.2'
+  spec.add_dependency 'concurrent-ruby', '~> 1.2'
 
   spec.add_development_dependency 'psych', '~> 4.0'
   spec.add_development_dependency 'rake', '~> 13.0'