diff --git a/Gemfile b/Gemfile
index 0ba3302..6f4c058 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,7 +2,7 @@
 source "https://rubygems.org"
 
 gem 'git', '~> 1.3'
-gem 'sinatra', '~> 2.0', '>= 2.0.4'
+gem 'sinatra', '~> 4.1', '>= 4.1.0'
 gem 'minitest', '~> 5.11', '>= 5.11.3'
 gem 'multi_json', '~> 1.13', '>= 1.13.1'
 gem 'mail', '~> 2.7'
diff --git a/Gemfile.lock b/Gemfile.lock
index eff6f10..7e603a7 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,32 +1,40 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    base64 (0.2.0)
     git (1.4.0)
     gitlab (4.4.0)
       httparty (>= 0.14.0)
       terminal-table (>= 1.5.1)
     httparty (0.16.2)
       multi_xml (>= 0.5.2)
+    logger (1.6.1)
     mail (2.7.0)
       mini_mime (>= 0.1.1)
     mini_mime (1.0.0)
     minitest (5.11.3)
     multi_json (1.13.1)
     multi_xml (0.6.0)
-    mustermann (1.1.1)
+    mustermann (3.0.3)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.3)
-    rack-protection (2.0.8.1)
-      rack
-    ruby2_keywords (0.0.2)
-    sinatra (2.0.8.1)
-      mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.8.1)
+    rack (3.1.8)
+    rack-protection (4.1.1)
+      base64 (>= 0.1.0)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
+    ruby2_keywords (0.0.5)
+    sinatra (4.1.1)
+      logger (>= 1.6.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.1.1)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
-    tilt (2.0.10)
+    tilt (2.4.0)
     unicode-display_width (1.4.0)
 
 PLATFORMS
@@ -38,7 +46,7 @@ DEPENDENCIES
   mail (~> 2.7)
   minitest (~> 5.11, >= 5.11.3)
   multi_json (~> 1.13, >= 1.13.1)
-  sinatra (~> 2.0, >= 2.0.4)
+  sinatra (~> 4.1, >= 4.1.0)
 
 BUNDLED WITH
    1.17.3