diff --git a/study_guides/rails/99cats_debugger/Gemfile.lock b/study_guides/rails/99cats_debugger/Gemfile.lock
index d341faf47..99ad5338d 100644
--- a/study_guides/rails/99cats_debugger/Gemfile.lock
+++ b/study_guides/rails/99cats_debugger/Gemfile.lock
@@ -102,7 +102,7 @@ GEM
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.11.3)
-    nio4r (2.5.2)
+    nio4r (2.5.8)
     nokogiri (1.10.9)
       mini_portile2 (~> 2.4.0)
     pg (1.1.4)
@@ -112,7 +112,7 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (3.1.1)
-    puma (4.3.5)
+    puma (4.3.12)
       nio4r (~> 2.0)
     rack (2.2.3)
     rack-test (1.1.0)