NopCommerce Recurring Paymens is only supported by PayPal and Authorze.Net.
Authorizie.Net is US only. So, that leaves just PayPal for businesses located outside of the US.

PayPal MTS are claiming the NopCommerce system does not work with their platform and is using a very old and obsolete API.

To make a response to the PayPal Merchant Technical Support (MTS) has ANYBODY EVER got Recurring Payments to work. Even on Sandbox?

There has been a siggestion that they will pull support for the Version 51 API that NopCommerce was coded to, which is very out of date and obsolete. So, that could spell a complete failure for shops using NopCommerce with PayPal.

Not to be an alarmist, but that would give all the developers who have provided this as a solution to their customers some real problems.

So, if anyone could give some feedback on the Recurring Payments, I would be grateful as right now it is a complete show stopper and no billing can occur for us using this NopCommerce on PayPal.
The matter is escalating with PayPal MTS.

Your responses would be really helpful.