bundle install shows "[DEPRECATED] Platform :mingw, :x64_mingw, :mswin will be removed in the future. Please use platform :windows instead."

Operating System

Windows 11

Ruby Version

ruby 4.0.5 (2026-05-20 revision 64336ffd0e) +PRISM [x64-mingw-ucrt]

Jekyll Version

jekyll 4.4.1

GitHub Pages Version

Latest

Expected Behavior

(because it's just a deprecation warning and not a bug, this issue doesn't quite fit this format but I couldn't find a matching issue category)

bundle install on a new jekyll project should run without warning.

Current Behavior

With the latest version of bundle, when running bundle install on a new jekyll project I get:

[DEPRECATED] Platform :mingw, :x64_mingw, :mswin will be removed in the future. Please use platform :windows instead.

(the operation still works)

The Gemfile contains:

# Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
# and associated library.
platforms :mingw, :x64_mingw, :mswin, :jruby do
  gem "tzinfo", ">= 1", "< 3"
  gem "tzinfo-data"
end

# Performance-booster for watching directories on Windows
gem "wdm", "~> 0.1", :platforms => [:mingw, :x64_mingw, :mswin]

So the Gemfile template of new projects created with jekyll new project_name should probably be updated to use:

# Windows and JRuby does not include zoneinfo files, so bundle the tzinfo-data gem
# and associated library.
platforms :windows, :jruby do
  gem "tzinfo", ">= 1", "< 3"
  gem "tzinfo-data"
end

# Performance-booster for watching directories on Windows
gem "wdm", "~> 0.1", :platforms => [:windows]

I verified that applying this change removed the deprecation warning.

Relevant log output

Code Sample

Steps to reproduce the issue

• jekyll new test_project
• cd test_project
• bundle install