diff --git a/back-end/Gemfile b/back-end/Gemfile
index 2f66f41..500e7d3 100644
--- a/back-end/Gemfile
+++ b/back-end/Gemfile
@@ -11,7 +11,7 @@ gem 'jwt', '~> 2.2', '>= 2.2.2'
 gem 'bcrypt', '~> 3.1', '>= 3.1.12'
 
 # Use Puma as the app server
-gem 'puma', '~> 3.12'
+gem 'puma', '~> 4.3'
 # Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
 # gem 'jbuilder', '~> 2.5'
 # Use Redis adapter to run Action Cable in production
diff --git a/back-end/Gemfile.lock b/back-end/Gemfile.lock
index 8376bc4..5e756d4 100644
--- a/back-end/Gemfile.lock
+++ b/back-end/Gemfile.lock
@@ -69,7 +69,9 @@ GEM
     marcel (0.3.3)
       mimemagic (~> 0.3.2)
     method_source (1.0.0)
-    mimemagic (0.3.5)
+    mimemagic (0.3.10)
+      nokogiri (~> 1)
+      rake
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.14.2)
@@ -77,7 +79,8 @@ GEM
     nio4r (2.5.3)
     nokogiri (1.10.10)
       mini_portile2 (~> 2.4.0)
-    puma (3.12.6)
+    puma (4.3.11)
+      nio4r (~> 2.0)
     rack (2.2.3)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
@@ -141,7 +144,7 @@ DEPENDENCIES
   byebug
   jwt (~> 2.2, >= 2.2.2)
   listen (>= 3.0.5, < 3.2)
-  puma (~> 3.12)
+  puma (~> 4.3)
   rack-cors
   rails (~> 5.2.1)
   spring