diff --git a/statsig.gemspec b/statsig.gemspec
index 2dda755..e93c7a9 100644
--- a/statsig.gemspec
+++ b/statsig.gemspec
@@ -32,5 +32,5 @@ Gem::Specification.new do |s|
   s.add_runtime_dependency 'connection_pool', '~> 2.4', '>= 2.4.1'
   s.add_runtime_dependency 'ip3country', '~> 0.2.1'
   s.add_runtime_dependency 'concurrent-ruby', '~> 1.1'
-  s.add_runtime_dependency 'zlib', '~> 3.1.0'
+  s.add_runtime_dependency 'zlib', '>= 3.1', '< 4.0'
 end