paypal sent payment but zen cart didn't record order

Thanks Dr Byte. I know our site is due for any upgrade, which we will do shortly, but in the mean time I cannot undertand why the IPN would stop working when we haven't changed our code in over 2 years.

Is this a common problem with Paypal?

Besides upgrading our site, is there any way I can work out why this is happening?

Thanks

You've already started a separate thread to deal with your unique sudden problem. Let's keep your discussion there: http://www.zen-cart.com/forum/showthread.php?t=143577