diff --git a/docs-book/Gemfile.lock b/docs-book/Gemfile.lock
index 3450239..2ce3d1f 100644
--- a/docs-book/Gemfile.lock
+++ b/docs-book/Gemfile.lock
@@ -156,7 +156,7 @@ GEM
     minitest (5.14.1)
     multi_json (1.14.1)
     multipart-post (2.1.1)
-    nio4r (2.5.2)
+    nio4r (2.5.9)
     nokogiri (1.10.1)
       mini_portile2 (~> 2.4.0)
     padrino-helpers (0.13.3.4)
@@ -167,7 +167,7 @@ GEM
       activesupport (>= 3.1)
     parallel (1.19.2)
     public_suffix (4.0.5)
-    puma (4.3.5)
+    puma (6.3.1)
       nio4r (~> 2.0)
     rack (1.6.13)
     rack-livereload (0.3.17)