diff --git a/Gemfile b/Gemfile
--- a/Gemfile
+++ b/Gemfile
@@ -6,8 +6,8 @@
 gem 'i18n'
 gem 'json'
 gem 'rest-client'
-gem 'sinatra'
+gem 'sinatra', '>= 2.0.4'
 
 group :development do
-  gem 'shotgun'
+  gem 'shotgun', '<= 0.9.2'
 end
diff --git a/Gemfile.lock b/Gemfile.lock
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -52,8 +52,8 @@
   i18n
   json
   rest-client
-  shotgun
-  sinatra
+  shotgun (<= 0.9.2)
+  sinatra (>= 2.0.4)
 
 BUNDLED WITH
    1.16.2