I am thrilled to announce the release of CSS3 PIE 2.0 beta 1! This is the first official release of the 2.0 development line, which has seen several major refactoring efforts to improve performance, enhance feature support, and fix many long-standing bugs.

The major changes from 1.0 are:

PIE.htc is now a very small (~2K) stub file which loads a secondary logic file optimized for the current IE version, resulting in a smaller total download size. See the blog post on the new loading system for details on how this works and its benefits. As a user this shouldn’t change how you use PIE, except that instead of only copying a single file you now need to copy all the files in the distribution directory together as a unit.

A new -pie-load-path property can be set in the CSS for the <html> element to customize where the secondary logic files are loaded from, for example an external CDN.

The VML renderers in IE 6-8 have been heavily refactored: the resulting DOM is smaller, and the VML is now initially built up as a single markup string and inserted all at once instead of using the DOM API. This makes the insertion faster, and also allows the use of certain VML features that could not be used before (e.g. o:opacity2).

The linear-gradient parsing has been updated to support the final spec syntax (the “to side” syntax and new angle origin.) You will need to update your CSS to the new syntax to avoid incorrect angles or blank rendering.

Linear gradients with rgba colors can now render the alpha channel in IE 6-8, but only for gradients with two stops.

Linear gradients in IE 9 are now rendered using Canvas rather than SVG, which allows it to display properly when used along with -ms-transform.

Box-shadow rendering in IE 6-8 now properly renders the alpha channel in rgba colors when the shadow has a blur radius.

Border-radius rendering in IE 6-8 has been refactored, fixing the “bumps on corners” bug when the border width is larger than the corner radius, adding support for groove/ridge/inset/outset borders, and improving transitions around corners between differing border styles. The new border-radius demo page shows the improved rendering.

The background-origin, background-size, and background-clip parameters within the -pie-background shorthand property are now supported for non-repeating backgrounds in IE 6-8.

Various other minor fixes; see the full changelog for details.

This is definitely an early beta, so it’s very likely there are many new bugs to be squashed. While the stable PIE 1.0.0 release is still the recommended version for public sites, I do encourage everyone to try out the beta and report back any bugs or other issues you may encounter in the new 2.0.x beta forum. Even if you don’t encounter problems, reporting back your success will also be helpful to help us gauge stability and move toward a swift final release.

Download PIE 2.0 beta 1 and give it a try!

Thanks everyone!