Edit History Lost After Upgrade to Yosemite and iPhoto 9.6

I recently upgraded to Yosemite and iPhoto 9.6. While going over some of my albums today I realized all the edit history has been lost from my iPhotos. When I open photos that I know I previously cropped, or adjusted for contrast, definition, etc., the photos don't show any crop history and all the adjustment points are reset as if there have never been any adjustments.

I can live with the lost edit history, but it looks like I can never recover the original image files.

Did I do something wrong during the software upgrade process? Are my original image files lost for good?