Duplicate Orders - Suspected from clicking Back button

I found several threads about duplicate orders, but only concerning problems specific to their vendor (AIM, PayPal).

On occasion, our shopping cart generates between 5 to 10 duplicate orders for customers. I have tried to duplicate the issue myself and found that the shopping cart generates duplicate orders when customers click on the Back button on the browser on the order confirmation screen.

It doesn't post the transaction more than once to our vendor, but generates duplicate emails to our order processing center and to the customer, each with different order numbers.
When this happens, we are able to determine which orders are duplicates as they are missing information on what product was ordered and the customer's shipping information, etc. Customers get very confused when this happens.

Is there a fix for this problem?

We are currently running version 1.2.5. The reason we have not updated is due to minor modification to cart functionality.
Our vendor is Merchant Anywhere.

Any help would be greatly appreciated!

bump
This is an important problem for our company. Any help would be much appreciated!

Safeties are built into Zen Cart v1.3.6 to prevent this from happening ...

You might look at the code and see if you can adapt this to your old, buggy, out of date code ...

At a minimum get to at least v1.2.7 and insert all of the security fixes for that version ...

Ok. Thank you for the response!
Due to the extent of our modifications to the cart, we won't be able to update to the latest version. I was hoping that there could be a code snippet that could solve the problem. Updates would overwrite core files that were modified, but am happy to hear that that issue was resolved with newer versions!

This would not be a little snippet of code ...

And to fix it for such old code would take quite a bit of work ...

You might post something in the Commercial Help Wanted to see if anyone is willing to delve into code that really has issues in itself, plus your customizations, plus security issues, plus issues on allowing the code to re-processes ... kinda scary there ... :unsure:

Be sure to only attempt to fix this on a test site and not your live site as much will be broken while testing and fixing the files to manage this better ...

I am concerned that you will be adding a lot of band-aides to something that has a sieve of leaks and issues and may not be pleased in the end with the results ...

Ok, thanks for your response Ajeh. I completely understand where you are coming from with the complexities of developing a solution for the problem and that there isn't a simple old patch to fix this. Since we will be revamping our shopping cart sometime in the next coming months, I doubt it would be worth the effort to ask for professional help.

Thanks again!

Just to add a second voice, Booch, I think Linda's right. You'd be far better off building a new site based on 1.3.6, re-adding your modifications, and starting again. This is why it's absolutely critical to stay on top of the new releases: you can bring your customizations through as the system gradually evolves.