diff --git a/spec/test_app_templates/Gemfile.extra b/spec/test_app_templates/Gemfile.extra
index 6805cce3..b8307873 100644
--- a/spec/test_app_templates/Gemfile.extra
+++ b/spec/test_app_templates/Gemfile.extra
@@ -2,8 +2,7 @@
 
 group :development do
   gem 'linkeddata'
-  case ENV['RAILS_VERSION']
-  when /^6\.[01]\./
+  if ENV['RAILS_VERSION'] =~ /^6\.1\./ && ENV['RUBY_VERSION'] =~ /^3\.1\./
     # Ruby 3.0 comes with Psych 3, while Ruby 3.1 comes with Psych 4,
     # which has a major breaking change (diff 3.3.2 → 4.0.0).
     # See: https://bugs.ruby-lang.org/issues/17866