diff --git a/play-with-docker/Portus/Gemfile b/play-with-docker/Portus/Gemfile
index e23be3343..04a7e0df2 100644
--- a/play-with-docker/Portus/Gemfile
+++ b/play-with-docker/Portus/Gemfile
@@ -52,7 +52,7 @@ def packaging?
 end
 
 # If the deployment is done through Puma, include it in the bundle.
-gem "puma", "~> 3.7.0" if ENV["PORTUS_PUMA_DEPLOYMENT"] == "yes" || !packaging?
+gem "puma", "~> 4.3.12" if ENV["PORTUS_PUMA_DEPLOYMENT"] == "yes" || !packaging?
 
 # In order to create the Gemfile.lock required for packaging
 # meaning that it should contain only the production packages
diff --git a/play-with-docker/Portus/Gemfile.lock b/play-with-docker/Portus/Gemfile.lock
index c1235180e..3a14a2f4f 100644
--- a/play-with-docker/Portus/Gemfile.lock
+++ b/play-with-docker/Portus/Gemfile.lock
@@ -191,6 +191,7 @@ GEM
     mysql2 (0.3.18)
     nenv (0.3.0)
     net-ldap (0.11)
+    nio4r (2.5.8)
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
     notiffany (0.0.8)
@@ -222,7 +223,8 @@ GEM
       activerecord (>= 3.0)
       i18n (>= 0.5.0)
       railties (>= 3.0.0)
-    puma (3.7.0)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     pundit (1.0.1)
       activesupport (>= 3.0.0)
     quiet_assets (1.1.0)
@@ -425,7 +427,7 @@ DEPENDENCIES
   poltergeist
   pry-rails
   public_activity
-  puma (~> 3.7.0)
+  puma (~> 4.3.12)
   pundit
   quiet_assets
   rack-mini-profiler