Added 4.0.1 release announcement

Author: hsbt

_posts/2025-12-09-4.0.1-released.md

@@ -0,0 +1,69 @@
+---
+title: 4.0.1 Released
+layout: post
+author: Hiroshi SHIBATA
+author_email: hsbt@ruby-lang.org
+---
+
+RubyGems 4.0.1 includes enhancements, bug fixes and documentation and Bundler 4.0.1 includes performance, enhancements and bug fixes.
+
+To update to the latest RubyGems you can run:
+
+    gem update --system [--pre]
+
+To update to the latest Bundler you can run:
+
+    gem install bundler [--pre]
+    bundle update --bundler=4.0.1
+
+## RubyGems Release Notes
+
+
+### Enhancements:
+
+* Installs bundler 4.0.1 as a default gem.
+
+### Bug fixes:
+
+* Fixed unexpected default bundler installation. Pull request
+  [#9167](https://github.com/ruby/rubygems/pull/9167) by hsbt
+
+### Documentation:
+
+* Update contributing docs with `RGV`. Pull request
+  [#9155](https://github.com/ruby/rubygems/pull/9155) by eileencodes
+
+
+## Bundler Release Notes
+
+
+### Performance:
+
+  - Increase connection pool to allow for up to 70% speed increase on `bundle install` [#9087](https://github.com/ruby/rubygems/pull/9087)
+
+### Enhancements:
+
+  - Fix the config suggestion in the warning for `$ bundle` [#9164](https://github.com/ruby/rubygems/pull/9164)
+  - Fix native extension loading in newgem template for RHEL-based systems [#9156](https://github.com/ruby/rubygems/pull/9156)
+
+### Bug fixes:
+
+  - Fix Bundler removing executables after creating them [#9169](https://github.com/ruby/rubygems/pull/9169)
+
+
+## Manual Installation
+
+To install RubyGems by hand see the [Download RubyGems][download] page.
+
+SHA256 Checksums:
+
+* rubygems-4.0.1.tgz  
+  efbdf2a575544198f0f9516dbffac2b0d576fbb504aea6d52d1976d0db512652
+* rubygems-4.0.1.zip  
+  98b829062f6f030603ed2243b9d05c6db6718c04b6d8589d68038474ec99adf3
+* rubygems-update-4.0.1.gem  
+  c2ff99782fc56f649d04edb3f88bbbb6c50d731d8dc87e2c0670dc79536e5c73
+
+
+[download]: https://rubygems.org/pages/download
+