diff --git a/simple-navigation-bootstrap.gemspec b/simple-navigation-bootstrap.gemspec
index 0805dff..535e2f2 100644
--- a/simple-navigation-bootstrap.gemspec
+++ b/simple-navigation-bootstrap.gemspec
@@ -18,6 +18,6 @@ Gem::Specification.new do |s|
 
   # specify any dependencies here; for example:
   s.add_development_dependency "rake"
-  s.add_runtime_dependency "simple-navigation", ">= 3.7.0"
+  s.add_runtime_dependency "simple-navigation", ">= 3.7.0", "< 4.0.0"
   s.add_runtime_dependency "railties", ">= 3.1"
 end