diff --git a/Gemfile b/Gemfile
index 746c449..0c3ae5d 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,13 +1,13 @@
 # frozen_string_literal: true
 
 source 'http://rubygems.org'
 gem 'activesupport'
 gem 'hashie'
 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
index d2fac90..e5e4de6 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,59 +1,59 @@
 GEM
   remote: http://rubygems.org/
   specs:
     activesupport (5.2.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
     concurrent-ruby (1.0.5)
     domain_name (0.5.20180417)
       unf (>= 0.0.5, < 1.0.0)
     hashie (3.6.0)
     http-cookie (1.0.3)
       domain_name (~> 0.5)
     i18n (1.1.0)
       concurrent-ruby (~> 1.0)
     json (2.1.0)
     mime-types (3.2.2)
       mime-types-data (~> 3.2015)
     mime-types-data (3.2018.0812)
     minitest (5.11.3)
     mustermann (1.0.3)
     netrc (0.11.0)
     rack (2.0.5)
     rack-protection (2.0.4)
       rack
     rest-client (2.0.2)
       http-cookie (>= 1.0.2, < 2.0)
       mime-types (>= 1.16, < 4.0)
       netrc (~> 0.8)
     shotgun (0.9.2)
       rack (>= 1.0)
     sinatra (2.0.4)
       mustermann (~> 1.0)
       rack (~> 2.0)
       rack-protection (= 2.0.4)
       tilt (~> 2.0)
     thread_safe (0.3.6)
     tilt (2.0.8)
     tzinfo (1.2.5)
       thread_safe (~> 0.1)
     unf (0.1.4)
       unf_ext
     unf_ext (0.0.7.5)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
   activesupport
   hashie
   i18n
   json
   rest-client
-  shotgun
-  sinatra
+  shotgun (<= 0.9.2)
+  sinatra (>= 2.0.4)
 
 BUNDLED WITH
    1.16.2