diff --git a/Gemfile b/Gemfile
index 77ac5a7e..d759c7c7 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,7 +12,7 @@ end
 gem 'rails', '~> 5.2'
 
 # Use Puma as the app server
-gem 'puma', '~> 3.0'
+gem 'puma', '~> 5.2'
 
 # respond_to methods have been extracted to the responders gem
 # http://edgeguides.rubyonrails.org/upgrading_ruby_on_rails.html#responders
diff --git a/Gemfile.lock b/Gemfile.lock
index 241cbb00..75f5f46a 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -415,7 +415,8 @@ GEM
       method_source (~> 0.8.1)
       slop (~> 3.4)
     public_suffix (3.1.1)
-    puma (3.12.6)
+    puma (5.2.1)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-openid (1.3.1)
@@ -736,7 +737,7 @@ DEPENDENCIES
   pronto-haml
   pronto-rubocop
   pry
-  puma (~> 3.0)
+  puma (~> 5.2)
   rails (~> 5.2)
   rails-assets-bootstrap-markdown!
   rails-assets-bootstrap-select!