My web app uses PayPal monthly subscriptions. I receive IPN notifications when payments are made, users signup/cancel, etc and this all seems to work well.
One thing that appears to be missing from the IPN messages is any sort of indication about the next billing date. https://developer.paypal.com/docs/classic/ipn/integration-guide/IPNandPDTVariables/#id091EB0901HT
At first I thought that since it's a monthly subscription, I can simply add a month to the previous date, but PayPal seems to have a funky way of figuring out the next payment date - it's not always 30 or 31 days or a month.
The next billing date is available from within PayPal itself, but doesn't seem to be sent along in any IPN messages.
Does anyone know of a simple way to work this out from the information that is available in the IPN messages?