Version 4.0.13 of Ruby's Bundler package-manager has added dependency cooldowns in order to help mitigate the effect of supply-chain attacks: Most supply-chain attacks against RubyGems exploit a narrow window: an account is compromised, a malicious version ships, and any bundle install in the minutes that follow resolves straight to it. Bundler 4.0.13 introduces cooldown, a time-based filter that refuses to resolve to a version until it has been public for at least N days. Releases too new to have been scrutinized are passed over in favor of ones that have aged past the window. The feature was designed in the open, drawing on how other ecosystems approach the same problem. It is opt-in, and complements rather than replaces existing defenses like mandatory 2FA and trusted publishing. LWN covered dependency cooldowns in April, and the takeover of RubyGems and Bundler in October 2025.