Just saw the news on the mootools mail list: 1.2.1 got released. It’s a minor bugfixing and performance-related update, with the most notable changes (for me anyway) the improved Safari 2 support:

[ADD] Element.set('html') now allows to set the innerHTML of all Elements (including tables and selects)
[ADD] Browser.Features.query to check if the Browser supports the new querySelector method on the document object
[ADD] Browser.Engine detection for WebKit version 525
[ADD] Browser.Engine detection for Opera 9.6
[ADD] Element.removeEvents now also accepts an object
[ADD] Class.removeEvents now also accepts an object
[ADD] Element.match now also accepts an Element
[CHG] Element.js has been refactored to make use of private variables wherever possible
[CHG] $unlink now returns an unlinked Hash instead of an object when a Hash is passed in
[CHG] Faster Element.hasChild
[CHG] The domready event for WebKit version 525 (or later) uses the native DomContentLoaded event
[FIX] Fixed getPosition in Internet Explorer to be faster and more reliable
[FIX] Selector [attribute!=val] now matches elements with empty attribute
[FIX] Element.clone is now much faster and retains state of form elements
[FIX] Fixed memory leaks related to IFrame unloading
[FIX] Fixed memory leaks related to Element storage
[FIX] Custom Events no longer stop the event when the condition returns false
[FIX] Documentation fixes and improvements
[FIX] :checked pseudo now works properly in Internet Explorer
[FIX] Class.js works in Safari 2 again, and contains no more eval hack
[FIX] Element text setter/getter is now working in Safari 2
[FIX] $exec is now working in Safari 2

Go and get it now