diff --git a/Gemfile b/Gemfile
index b7d256a..4888618 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem "rails", "~> 5.2.1"
 # Use postgresql as the database for Active Record
 gem "pg", ">= 0.18", "< 2.0"
 # Use Puma as the app server
-gem "puma", "~> 3.12"
+gem "puma", "~> 4.3"
 # Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
 gem "webpacker"
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
diff --git a/Gemfile.lock b/Gemfile.lock
index 9689e73..11eb9f1 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -102,7 +102,9 @@ 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_magick (4.9.3)
     mini_mime (1.0.1)
     mini_portile2 (2.4.0)
@@ -117,7 +119,8 @@ GEM
       ast (~> 2.4.0)
     pg (1.1.4)
     public_suffix (3.1.0)
-    puma (3.12.1)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-proxy (0.6.4)
       rack
@@ -246,7 +249,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mini_magick (~> 4.9)
   pg (>= 0.18, < 2.0)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rails (~> 5.2.1)
   rspec-rails (~> 3.8)
   rspec_junit_formatter