Invisalign is constantly trying to improve their product.

Recently they introduced Invisalign Teen.  This product helps dentists treat younger patients by including:

In addition, many improvements have been made to their existing product lines.  These include improvements in rotating, erupting, and intruding teeth.  They have also optimized tooth movement so that the whole tooth moves rather than just tips.  More information can be found by clicking the  following:

Invisalign news release

Or by watching this video:

Invisalign Improvements