diff --git a/Gemfile b/Gemfile
index d9fe9897..3071ce80 100644
--- a/Gemfile
+++ b/Gemfile
@@ -10,7 +10,7 @@ gem 'rails', '>= 6.0.3.1'
 gem 'recaptcha', '~> 5.8', require: 'recaptcha/rails'
 gem 'sassc', '~> 2.4'
 gem 'sassc-rails'
-gem 'simpleidn', '0.0.7' # For Punycode
+gem 'simpleidn', '0.2.1' # For Punycode
 gem 'uglifier'
 gem 'passenger', '>= 5.3.2', require: 'phusion_passenger/rack_handler'
 
diff --git a/Gemfile.lock b/Gemfile.lock
index 7364c817..0d375c66 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -206,7 +206,8 @@ GEM
       json (>= 1.8, < 3)
       simplecov-html (~> 0.10.0)
     simplecov-html (0.10.2)
-    simpleidn (0.0.7)
+    simpleidn (0.2.1)
+      unf (~> 0.1.4)
     sprockets (4.0.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
@@ -221,6 +222,9 @@ GEM
       concurrent-ruby (~> 1.0)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
+    unf (0.1.4)
+      unf_ext
+    unf_ext (0.0.7.7)
     unicorn (6.0.0)
       kgio (~> 2.6)
       raindrops (~> 0.7)
@@ -258,7 +262,7 @@ DEPENDENCIES
   sassc-rails
   selenium-webdriver
   simplecov (= 0.17.1)
-  simpleidn (= 0.0.7)
+  simpleidn (= 0.2.1)
   uglifier
   unicorn
   webmock