diff --git a/Gemfile b/Gemfile
index c10abd72..8ccf3cf2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,3 +1,3 @@
 source 'https://rubygems.org'
 
-gem 'sinatra'
+gem 'sinatra', '>= 4.2.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index 6c1bfaba..e15d796a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,26 +1,33 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    base64 (0.2.0)
-    mustermann (3.0.3)
+    base64 (0.3.0)
+    logger (1.7.0)
+    mustermann (3.0.4)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.13)
-    rack-protection (3.2.0)
+    rack (3.2.3)
+    rack-protection (4.2.1)
       base64 (>= 0.1.0)
-      rack (~> 2.2, >= 2.2.4)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.1.1)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0)
     ruby2_keywords (0.0.5)
-    sinatra (3.2.0)
+    sinatra (4.2.1)
+      logger (>= 1.6.0)
       mustermann (~> 3.0)
-      rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.2.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.2.1)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    tilt (2.6.0)
+    tilt (2.6.1)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  sinatra
+  sinatra (>= 4.2.0)
 
 BUNDLED WITH
-   1.17.2
+   2.3.27