Gravity Forms v1.6.4.2 is now available via automatic update. This is an important maintenance releases that resolves javascript issues related to WordPress themes not properly implementing the jQuery javascript library. This release also implements improvements and refinements to new calculation functionality introduced in Gravity Forms v1.6.4.
The major issue this release resolves is a javascript error caused by themes that are enqueuing their own outdated version of jQuery or enqueuing an outdated version of jQuery from an external source such as Google's jQuery API. WordPress comes with jQuery, there is no reason to use any other jQuery than what is built into WordPress. Doing so only leads to headaches down the road.
We implemented a work around to support these situations, however WordPress theme developers could do the entire WordPress community a huge favor by learning the proper way to use jQuery within their themes and then workarounds such as this would not be necessary.
You can update to the latest version of Gravity Forms using Automatic Update. Just visit the Updates page under the Forms navigation in your WordPress Dashboard. Update deployment is staged so if you do not see the update available, try again in a few hours. You can also download the latest version of the plugin from the Downloads page.