diff --git a/src/emailservice/Gemfile b/src/emailservice/Gemfile
index f4548ea..cc04e56 100644
--- a/src/emailservice/Gemfile
+++ b/src/emailservice/Gemfile
@@ -5,7 +5,7 @@ source "https://rubygems.org"
 gem "net-smtp", "~> 0.3"
 gem "pony",     "~> 1.13"
 gem "puma",     "~> 6.3"
-gem "sinatra",  "~> 3.0"
+gem "sinatra", "~> 4.1", ">= 4.1.0"
 
 gem "opentelemetry-sdk", "~> 1.2"
 gem "opentelemetry-exporter-otlp", "~> 0.24"
diff --git a/src/emailservice/Gemfile.lock b/src/emailservice/Gemfile.lock
index 98c10c6..8403570 100644
--- a/src/emailservice/Gemfile.lock
+++ b/src/emailservice/Gemfile.lock
@@ -1,18 +1,21 @@
 GEM
   remote: https://rubygems.org/
   specs:
+    base64 (0.2.0)
     date (3.3.3)
+    google-protobuf (3.23.4)
     google-protobuf (3.23.4-aarch64-linux)
     google-protobuf (3.23.4-arm64-darwin)
     googleapis-common-protos-types (1.7.0)
       google-protobuf (~> 3.14)
+    logger (1.6.1)
     mail (2.8.1)
       mini_mime (>= 0.1.1)
       net-imap
       net-pop
       net-smtp
     mini_mime (1.1.2)
-    mustermann (3.0.0)
+    mustermann (3.0.3)
       ruby2_keywords (~> 0.0.1)
     net-imap (0.3.6)
       date
@@ -218,22 +221,29 @@ GEM
       mail (>= 2.0)
     puma (6.3.0)
       nio4r (~> 2.0)
-    rack (2.2.7)
-    rack-protection (3.0.6)
-      rack
+    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 (3.0.6)
+    sinatra (4.1.1)
+      logger (>= 1.6.0)
       mustermann (~> 3.0)
-      rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.0.6)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.1.1)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    tilt (2.2.0)
+    tilt (2.4.0)
     timeout (0.4.0)
 
 PLATFORMS
   aarch64-linux
   arm64-darwin-21
   arm64-darwin-22
+  ruby
 
 DEPENDENCIES
   net-smtp (~> 0.3)
@@ -242,7 +252,7 @@ DEPENDENCIES
   opentelemetry-sdk (~> 1.2)
   pony (~> 1.13)
   puma (~> 6.3)
-  sinatra (~> 3.0)
+  sinatra (~> 4.1, >= 4.1.0)
 
 BUNDLED WITH
    2.3.7