diff --git a/Gemfile b/Gemfile
index a492af7..06ccb45 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.3'
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index 5179b52..0ed7b2d 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -90,6 +90,7 @@ GEM
     duktape (2.3.0.0)
     erubi (1.9.0)
     execjs (2.7.0)
+    ffi (1.11.2)
     ffi (1.11.2-x64-mingw32)
     globalid (0.4.2)
       activesupport (>= 4.2.0)
@@ -114,13 +115,17 @@ GEM
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.13.0)
+    msgpack (1.3.1)
     msgpack (1.3.1-x64-mingw32)
     nio4r (2.5.2)
+    nokogiri (1.10.5)
+      mini_portile2 (~> 2.4.0)
     nokogiri (1.10.5-x64-mingw32)
       mini_portile2 (~> 2.4.0)
     orm_adapter (0.5.0)
     public_suffix (4.0.1)
-    puma (3.12.1)
+    puma (4.3.9)
+      nio4r (~> 2.0)
     rack (2.0.7)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -208,6 +213,7 @@ GEM
 
 PLATFORMS
   x64-mingw32
+  x86_64-linux
 
 DEPENDENCIES
   bootsnap (>= 1.1.0)
@@ -219,7 +225,7 @@ DEPENDENCIES
   devise
   duktape
   jbuilder (~> 2.5)
-  puma (~> 3.11)
+  puma (~> 4.3)
   rails (~> 5.2.3)
   sass-rails (~> 5.0)
   selenium-webdriver