diff --git a/GMStepper.podspec b/GMStepper.podspec
index d3fbb7a..fc0aa5c 100644
--- a/GMStepper.podspec
+++ b/GMStepper.podspec
@@ -12,4 +12,5 @@ Pod::Spec.new do |s|
   s.platform     = :ios, '8.0'
   s.requires_arc = true
   s.source_files = 'GMStepper/*.swift'
+  s.swift_version = '4.2'
 end