Sam Stephenson, released Prototype 184.108.40.206 to address several compatibility and performance issues and to protect against a potential security issue for developers using Prototype outside of a web browser environment.
Prototype 220.127.116.11 is a backwards-compatible, drop-in replacement recommended for all 1.6.0 users. We’ve fixed 28 bugs and made over a dozen improvements to the code base, including performance improvements for CSS selectors in Safari 3 and for the Element#up/#down/#next/#previous and Event#findElement methods in all browsers. We’re also now officially supporting the Opera browser, version 9.25 and higher. You can get the full scoop on all the changes in the [18.104.22.168 Changelog].