A few days ago, I posted a long-overdue XRegExp bug fix release (version 1.5.1). This was mainly to address an IE issue that a number of people have written to me and blogged about. Specifically,
RegExp.prototype.exec no longer throws an error in IE when it is simultaneously provided a nonstring argument and called on a regex with a capturing group that matches an empty string. That's an edge case of an edge case, but it was causing XRegExp to conflict with jQuery 1.7.1 (oops). You can see the full list of changes in the changelog.
But wait, there's more… XRegExp's Unicode plugin has been updated to support Unicode 6.1 (released January 2012), rather than Unicode 5.2. I've also added a new test suite with 265 tests so far, and more on the way.