If you do not recognize this URL, you may be using a service provider that is using IPN on your behalf. Please contact your service provider with the above information. If this problem continues, IPNs may be disabled for your account.
Thank you for your prompt attention to this issue.
Idiots. The IPN was updated to the new one 1 month ago.
Double checked that my IPN matches between Paypal and WHMCS
Apache 2.2 / PHP 5.2.5 / MySQL 5
Some time back i moved my clientexec billing to a new domain as 2checkout only allow me to use it on my sales site (billing as on its own domain). ClientExec support told old IPN will not work, but i got it working by parking old domain over new domain. So when paypal posts IPN, same script get it.
Since the file is different in your cause, you may need to use some .htaccess direct. I never contacted paypal regarding the IPN url change, if they can do it, it is easy, but i doubt they will be doing that as it involve some work.