diff --git a/filestack-rails.gemspec b/filestack-rails.gemspec
index 18aa0d3..ac19df9 100644
--- a/filestack-rails.gemspec
+++ b/filestack-rails.gemspec
@@ -17,7 +17,7 @@ Gem::Specification.new do |s|
   s.files = Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"]
 
   s.add_dependency 'rails', '>= 4.0'
-  s.add_dependency "filestack", '~> 2.9.1'
+  s.add_dependency "filestack", '~> 2.9', '>= 2.9.1'
 
   s.add_development_dependency 'coveralls'
   s.add_development_dependency 'sqlite3', '~> 1.3', '>= 1.3.6'