To the best of my knowledge, no one has been able to edit recipes submitted prior to the upgrades. We've also lost the ability to post additional pictures. I'd suggest using the "Feedback" link in the lower right corner from the recipes you want to edit, and sending messages to Ray. There doesn't seem to be a problem editing recipes submitted after the upgrade.
Just a thought here: You could resubmit the recipe with the changes and include the word updated at the end of the title. I'd reference the original with the URL so people can easily get to the comment history for the recipe. Then enter a comment on the original version, IN BOLD, referring people to the updated version, including the URL for the updated version. The downside of this would be if people keep posting comments to the older version. If you do try this, I'd suggest monitoring your "Track" pretty closely. If comments are made on the older version, you could gently nudge them to the update.
I personally appreciate knowing the date of any edit / update. I usually put the word Edited or Updated and the date in bold at the top of the frame. In the case of recipes, I'd probably put it at the beginning of the introductory comments.