diff --git a/refile.gemspec b/refile.gemspec
index 73725fc..ee34dd7 100644
--- a/refile.gemspec
+++ b/refile.gemspec
@@ -14,6 +14,6 @@ Gem::Specification.new do |spec|
 
   spec.required_ruby_version = ">= 2.1.0"
 
-  spec.add_dependency "sinatra", ">= 2.0.0", "<= 3.0.0"
+  spec.add_dependency "sinatra", ">= 2.0.0", "<= 5.0.0"
   spec.add_dependency "mime-types"
 end