1 files changed, 1 insertions, 1 deletions
diff --git a/Gemfile b/Gemfile
index 05f1cd44f5..371406cfde 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,7 +2,7 @@ source "https://rubygems.org"
 
 gemspec
 
-gem "activesupport", :group => :compat_testing, :platform => "ruby"
+gem "activesupport", "< 4.0.0", :group => :compat_testing, :platform => "ruby"
 
 group(:docgen) do
   gem "ronn"