Added 4.0.15 release announcement

Author: hsbt

_posts/2026-06-24-4.0.15-released.md

@@ -0,0 +1,67 @@
+---
+title: 4.0.15 Released
+layout: post
+author: Hiroshi SHIBATA
+author_email: hsbt@ruby-lang.org
+---
+
+RubyGems 4.0.15 includes enhancements and bug fixes and Bundler 4.0.15 includes 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=4.0.15
+
+## RubyGems Release Notes
+
+
+### Enhancements:
+
+* Rubygems: Fix Gem::Request for PQC support, adding integration connection tests. Pull request [#9615](https://github.com/ruby/rubygems/pull/9615) by junaruga
+* Reduce peak memory usage of full index loading and bundle install. Pull request [#9618](https://github.com/ruby/rubygems/pull/9618) by hsbt
+* Installs bundler 4.0.15 as a default gem.
+
+### Bug fixes:
+
+* Forward security policy to old-format gems. Pull request [#9611](https://github.com/ruby/rubygems/pull/9611) by hsbt
+
+
+## Bundler Release Notes
+
+
+### Enhancements:
+
+* Resolve Git LFS files in git sources from the real remote. Pull request [#9632](https://github.com/ruby/rubygems/pull/9632) by hsbt
+* Suggest access issues, not only yanking, for missing locked gems. Pull request [#9631](https://github.com/ruby/rubygems/pull/9631) by hsbt
+* Implement a make jobserver (continuation of #9210). Pull request [#9625](https://github.com/ruby/rubygems/pull/9625) by hsbt
+* Reduce peak memory usage of full index loading and bundle install. Pull request [#9618](https://github.com/ruby/rubygems/pull/9618) by hsbt
+* Bump up to rb-sys 0.9.128. Pull request [#9569](https://github.com/ruby/rubygems/pull/9569) by hsbt
+
+### Bug fixes:
+
+* Skip the make jobserver on Windows. Pull request [#9630](https://github.com/ruby/rubygems/pull/9630) by hsbt
+* Don't require source plugins to be installed to parse a lockfile: 4.0.x. Pull request [#9621](https://github.com/ruby/rubygems/pull/9621) by hsbt
+* Exempt lockfile versions from cooldown on every resolution path. Pull request [#9619](https://github.com/ruby/rubygems/pull/9619) by hsbt
+* Set `Bundler.settings[:ssl_ca_cert]` to download gems. Pull request [#9610](https://github.com/ruby/rubygems/pull/9610) by junaruga
+
+
+## Manual Installation
+
+To install RubyGems by hand see the [Download RubyGems][download] page.
+
+SHA256 Checksums:
+
+* rubygems-4.0.15.tgz  
+  ec63459a0746d6e33804c0d6cbbcd1bcc6359f44fcada267b0f489cc84083687
+* rubygems-4.0.15.zip  
+  54e30f36e5dbf193e1abbb1d6f995a83d3f1bcab0ff4cfe21064c8a3cb9554ed
+* rubygems-update-4.0.15.gem  
+  bb22f30d9172f4ecd646c2bc8de341a820814401bcada5d7c5c541bd63b8f427
+
+
+[download]: https://rubygems.org/pages/download
+