diff --git a/materials/canonical/session19/WebApp/Gemfile.lock b/materials/canonical/session19/WebApp/Gemfile.lock
index 222db1c..ac493de 100644
--- a/materials/canonical/session19/WebApp/Gemfile.lock
+++ b/materials/canonical/session19/WebApp/Gemfile.lock
@@ -1,18 +1,27 @@
 GEM
   remote: https://rubygems.org/
   specs:
-    mustermann (3.0.0)
+    base64 (0.2.0)
+    logger (1.6.6)
+    mustermann (3.0.3)
       ruby2_keywords (~> 0.0.1)
-    rack (2.2.8)
-    rack-protection (3.1.0)
-      rack (~> 2.2, >= 2.2.4)
+    rack (3.1.11)
+    rack-protection (4.1.0)
+      base64 (>= 0.1.0)
+      logger (>= 1.6.0)
+      rack (>= 3.0.0, < 4)
+    rack-session (2.1.0)
+      base64 (>= 0.1.0)
+      rack (>= 3.0.0)
     ruby2_keywords (0.0.5)
-    sinatra (3.1.0)
+    sinatra (4.1.0)
+      logger (>= 1.6.0)
       mustermann (~> 3.0)
-      rack (~> 2.2, >= 2.2.4)
-      rack-protection (= 3.1.0)
+      rack (>= 3.0.0, < 4)
+      rack-protection (= 4.1.0)
+      rack-session (>= 2.0.0, < 3)
       tilt (~> 2.0)
-    tilt (2.3.0)
+    tilt (2.6.0)
 
 PLATFORMS
   ruby