diff --git a/projects/bench_bnb_redux/solution/Gemfile b/projects/bench_bnb_redux/solution/Gemfile
index bf090805..9d6becc7 100644
--- a/projects/bench_bnb_redux/solution/Gemfile
+++ b/projects/bench_bnb_redux/solution/Gemfile
@@ -11,7 +11,7 @@ gem 'rails', '~> 5.1.2'
 # Use postgresql as the database for Active Record
 gem 'pg', '~> 0.18'
 # Use Puma as the app server
-gem 'puma', '~> 3.7'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/projects/bench_bnb_redux/solution/Gemfile.lock b/projects/bench_bnb_redux/solution/Gemfile.lock
index 2e04aec9..5153ced0 100644
--- a/projects/bench_bnb_redux/solution/Gemfile.lock
+++ b/projects/bench_bnb_redux/solution/Gemfile.lock
@@ -109,7 +109,8 @@ GEM
     pry-rails (0.3.6)
       pry (>= 0.10.4)
     public_suffix (3.0.2)
-    puma (3.11.4)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     rack (2.0.4)
     rack-test (1.0.0)
       rack (>= 1.0, < 3)
@@ -201,7 +202,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   pg (~> 0.18)
   pry-rails
-  puma (~> 3.7)
+  puma (~> 4.3)
   rails (~> 5.1.2)
   sass-rails (~> 5.0)
   selenium-webdriver