diff --git a/Gemfile.lock b/Gemfile.lock
index 8c19599..4276373 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -60,6 +60,7 @@ GEM
     multi_xml (0.6.0)
     multipart-post (2.0.0)
     netrc (0.11.0)
+    nio4r (2.5.8)
     nokogiri (1.10.1)
       mini_portile2 (~> 2.4.0)
     oauth2 (1.4.0)
@@ -131,7 +132,8 @@ GEM
       css_parser (>= 1.6.0)
       htmlentities (>= 4.0.0)
     public_suffix (3.0.2)
-    puma (3.11.3)
+    puma (4.3.12)
+      nio4r (~> 2.0)
     rack (1.6.11)
     rack-ssl (1.4.1)
       rack