diff --git a/30_sources/SRC_Zupfnoter/Gemfile.lock b/30_sources/SRC_Zupfnoter/Gemfile.lock
index 9b6cf597..c82b1eaf 100644
--- a/30_sources/SRC_Zupfnoter/Gemfile.lock
+++ b/30_sources/SRC_Zupfnoter/Gemfile.lock
@@ -47,7 +47,7 @@ GEM
     pry (0.12.2)
       coderay (~> 1.1.0)
       method_source (~> 0.9.0)
-    rack (2.0.6)
+    rack (2.2.3)
     rake (12.3.2)
     rb-fsevent (0.10.3)
     rb-inotify (0.10.0)