You can read the complete scoop here, just to get you warmed up, here’s some of the newly added goodness:
- CSS selectors ($$ and assorted methods) got a complete overhaul, and are blazing fast now; plus they support most CSS3 features.
- Built-in JSON support—plus a great tutorial on how to use it
The API documentation has been updated to reflect this, so there’s no excuse not to make the jump to Prototype 1.5.1—if you do find any issue, please report it.
Update: If you want to use Prototype 1.5.1_rc0 with script.aculo.us, be aware the the current 1.7.0 version requires Prototype 1.5.0, so be sure to grab the latest and greatest SVN trunk version of script.aculo.us which works fine with Prototype 1.5.1, and takes advantage of the updates. A script.aculo.us 1.7.1 release candidate should be coming soon…Tweet