diff --git a/config-server-sidecar/go.mod b/config-server-sidecar/go.mod
new file mode 100644
index 0000000..628c960
--- /dev/null
+++ b/config-server-sidecar/go.mod
@@ -0,0 +1,3 @@
+module example.com/configserver
+
+go 1.21
diff --git a/sidecar-dependent-app/Gemfile b/sidecar-dependent-app/Gemfile
index 4ef3816..778bbe3 100644
--- a/sidecar-dependent-app/Gemfile
+++ b/sidecar-dependent-app/Gemfile
@@ -3,6 +3,8 @@ source "http://rubygems.org"
 gem "sinatra"
 gem "json"
 gem "typhoeus"
+gem 'webrick'
+gem 'rackup'
 
 group :test, :development do
   gem "rspec"
diff --git a/sidecar-dependent-app/Gemfile.lock b/sidecar-dependent-app/Gemfile.lock
index 7da8d19..4fb9260 100644
--- a/sidecar-dependent-app/Gemfile.lock
+++ b/sidecar-dependent-app/Gemfile.lock
@@ -1,38 +1,49 @@
 GEM
   remote: http://rubygems.org/
   specs:
-    diff-lcs (1.3)
-    ethon (0.12.0)
-      ffi (>= 1.3.0)
-    ffi (1.10.0)
-    json (2.1.0)
-    mustermann (1.0.3)
-    rack (2.0.6)
-    rack-protection (2.0.4)
-      rack
-    rack-test (0.8.3)
-      rack (>= 1.0, < 3)
-    rspec (3.7.0)
-      rspec-core (~> 3.7.0)
-      rspec-expectations (~> 3.7.0)
-      rspec-mocks (~> 3.7.0)
-    rspec-core (3.7.1)
-      rspec-support (~> 3.7.0)
-    rspec-expectations (3.7.0)
+    base64 (0.2.0)
+    diff-lcs (1.5.1)
+    ethon (0.16.0)
+      ffi (>= 1.15.0)
+    ffi (1.16.3)
+    json (2.7.1)
+    mustermann (3.0.0)
+      ruby2_keywords (~> 0.0.1)
+    rack (3.0.10)
+    rack-protection (4.0.0)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
+    rack-test (2.1.0)
+      rack (>= 1.3)
+    rackup (2.1.0)
+      rack (>= 3)
+      webrick (~> 1.8)
+    rspec (3.13.0)
+      rspec-core (~> 3.13.0)
+      rspec-expectations (~> 3.13.0)
+      rspec-mocks (~> 3.13.0)
+    rspec-core (3.13.0)
+      rspec-support (~> 3.13.0)
+    rspec-expectations (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.7.0)
-    rspec-mocks (3.7.0)
+      rspec-support (~> 3.13.0)
+    rspec-mocks (3.13.0)
       diff-lcs (>= 1.2.0, < 2.0)
-      rspec-support (~> 3.7.0)
-    rspec-support (3.7.1)
-    sinatra (2.0.4)
-      mustermann (~> 1.0)
-      rack (~> 2.0)
-      rack-protection (= 2.0.4)
+      rspec-support (~> 3.13.0)
+    rspec-support (3.13.1)
+    ruby2_keywords (0.0.5)
+    sinatra (4.0.0)
+      mustermann (~> 3.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.0.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    tilt (2.0.9)
-    typhoeus (1.3.1)
+    tilt (2.3.0)
+    typhoeus (1.4.1)
       ethon (>= 0.9.0)
+    webrick (1.8.1)
 
 PLATFORMS
   ruby
@@ -40,9 +51,9 @@ PLATFORMS
 DEPENDENCIES
   json
   rack-test
+  rackup
   rspec
   sinatra
   typhoeus
+  webrick
 
-BUNDLED WITH
-   1.17.3
diff --git a/sidecar-dependent-app/manifest.yml b/sidecar-dependent-app/manifest.yml
index 9a8a224..cb3c563 100644
--- a/sidecar-dependent-app/manifest.yml
+++ b/sidecar-dependent-app/manifest.yml
@@ -5,7 +5,7 @@ applications:
   memory: 256M
   env:
     CONFIG_SERVER_PORT: 8082
-  stack: cflinuxfs3
+  stack: cflinuxfs4
   sidecars:
   - name: config-server
     process_types: