Their announcements are starting to trickle in:

http://www.dvinfo.net/news/canon-enhances-xf305-and-xf300-with-new-3d-capabilities.html

Just a quick note for clarification, this particular firmware upgrade
will be available later this summer. There's a firmware update that's
just been released for the X305 and XF300, but it's not this particular
package.

Yeah, it looks like the firmware that was released yesterday was only to add support for additional CF cards from Lexar.:

http://usa.canon.com/cusa/consumer/products/camcorders/professional_camcorders/xf305#DriversAndSoftware

Really happy to know that the XF300/305 cameras will be getting the dual recording feature.

Looks like this is the firmware that came out this week - 1.0.2.0. Did the update tonight and all went well. No issues. Make sure to do the Transfer Menu/CP to your normal SD card, do the upgrade on a different SD card, and then restore your Menu/CP files. Then your camera will be set up as you had it before (still have to set time zone, time and date).

Larry