CodeKit 2.0 has been deprecated. It will not receive any additional updates and you should not use it any longer.
If you already own a CodeKit 2 license, when you install version 3.0, EVERY feature that was part of 2.0 will remain totally unlocked, forever, for free. The app won't bother you with any upgrade prompts or "trial version" banners, either. You get a new UI, massive improvements under the hood, a bunch of little features I was too lazy to lock, and continued updates—free.
Of course, the new 3.0 features will be locked after a 10-day trial. If you decide they're worth it, upgrade your license and they're yours.
This liberal upgrade policy is why I have dropped support for 2.0 immediately. There's simply no reason to continue running that version of CodeKit. If you need it, however, you can download the last release here:
This version of the app is no longer available. CodeKit 1.0 originally launched in November, 2011 and was discontinued in April, 2014.
The tools and compilers in CodeKit 1.x are over three years out of date and can no longer be trusted to produce correct output.
CodeKit 1.0 was amazing for its day, but the bleeding edge of web development moves fast.