Version 1.5.9.1 is available via the WordPress repository. This update is very important for PayPal Standard users who are on version 1.5.9.

I’ve totally rewritten the IPN handler code. It’s much cleaner now and will be easier to maintain vs the various PayPal APIs. I’ve done as much testing as I can, and this is the best version of the plugin for PayPal yet. If you notice issues with checkouts or renewals, please contact me as soon as possible and I will fix it right away.
Thanks
= 1.5.9.1 =
* Revamped the ipnhandler code. It’s much cleaner now and should be easier to support with all 3 PayPal APIs (Standard, Website Payments Pro, Express) working through the one handler.
* Added Payflow Pro as a gateway option. Currently, only one-time charges is supported.
* Added the pmpro_register_redirect filter to allow you to change the URL PMPro redirects wp-login.php?action=register to. Returning false or an empty string will result in no redirect from the register page.
* Added pmpro_subscription_payment_failed hook that runs if a failed payment comes in through the IPN Handler, Authorize.net silent post, or Stripe web hook. do_action(“pmpro_subscription_payment_failed”, $old_order); $old_order is a MemberOrder object.