diff --git a/flip.gemspec b/flip.gemspec
index 311d676..020aac0 100644
--- a/flip.gemspec
+++ b/flip.gemspec
@@ -18,7 +18,7 @@ Gem::Specification.new do |s|
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
   s.require_paths = ["lib"]
 
-  s.add_dependency("activesupport", ">= 4.0", "<= 5.2")
+  s.add_dependency("activesupport", ">= 4.0", "< 6")
   s.add_dependency("i18n")
 
   s.add_development_dependency("actionpack")