diff --git a/pkgs/development/ruby-modules/bundler/default.nix b/pkgs/development/ruby-modules/bundler/default.nix
index 04f97c68c6a..8daf8040020 100644
--- a/pkgs/development/ruby-modules/bundler/default.nix
+++ b/pkgs/development/ruby-modules/bundler/default.nix
@@ -1,14 +1,31 @@
-{ buildRubyGem, ruby }:
+{ lib, buildRubyGem, ruby, writeScript }:
 
 buildRubyGem rec {
   inherit ruby;
   name = "${gemName}-${version}";
   gemName = "bundler";
-  version = "2.3.20";
-  source.sha256 = "sha256-gJJ3vHzrJo6XpHS1iwLb77jd9ZB39GGLcOJQSrgaBHw=";
+  version = "2.3.21";
+  source.sha256 = "sha256-+u3H/8Fno8U7ZMRj2me1DVvkOAR2HeWmjdo0TCG/0d4=";
   dontPatchShebangs = true;
 
+  passthru.updateScript = writeScript "gem-update-script" ''
+    #!/usr/bin/env nix-shell
+    #!nix-shell -i bash -p curl common-updater-scripts jq
+
+    set -eu -o pipefail
+
+    latest_version=$(curl -s https://rubygems.org/api/v1/gems/${gemName}.json | jq --raw-output .version)
+    update-source-version ${gemName} "$latest_version"
+  '';
+
   postFixup = ''
     sed -i -e "s/activate_bin_path/bin_path/g" $out/bin/bundle
   '';
+
+  meta = with lib; {
+    description = "Manage your Ruby application's gem dependencies";
+    homepage = "https://bundler.io";
+    license = licenses.mit;
+    maintainers = with maintainers; [anthonyroussel];
+  };
 }