“Prototype 1.6.0.2 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.” – Download – Changelog – Announcement