diff --git a/Gemfile b/Gemfile
index 6b4c3d1..f5c4feb 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,7 +6,7 @@ gem 'pg_search',                '~> 0.7.3'
 gem 'active_model_serializers', '~> 0.8.1'
 gem 'responders',               '~> 2.4.1'
 gem 'rack-cors',                '~> 1.0', '>= 1.0.3', require: 'rack/cors'
-gem 'puma',                     '~> 3.12.6'
+gem 'puma',                     '~> 4.3.12'
 
 group :test do
   gem 'rspec', '~> 3.8'
diff --git a/Gemfile.lock b/Gemfile.lock
index f472d79..61e0954 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -62,7 +62,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (0.9.2)
-    mimemagic (0.3.3)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.1)
     mini_portile2 (2.5.0)
     minitest (5.11.3)
@@ -75,7 +77,8 @@ GEM
       activerecord (>= 3.1)
       activesupport (>= 3.1)
       arel
-    puma (3.12.6)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     racc (1.5.2)
     rack (2.2.3)
     rack-cors (1.0.3)
@@ -152,7 +155,7 @@ DEPENDENCIES
   active_model_serializers (~> 0.8.1)
   pg (~> 1.1.4)
   pg_search (~> 0.7.3)
-  puma (~> 3.12.6)
+  puma (~> 4.3.12)
   rack-cors (~> 1.0, >= 1.0.3)
   rails (= 5.2.3)
   responders (~> 2.4.1)