I'm using PayPal-PHP-SDK for billing agreement api. I want to add new new card to existing billing agreement.
https://developer.paypal.com/docs/api/payments.billing-agreements/v1/
I've check docs and SDK there is not any proper way to update the card in billing agreement.
Your suggestion would be greatly appreciated
The PayPal-PHP-SDK is deprecated and not compatible with the current version of PayPal Subscriptions, which do not use a billing agreement for anything. There is no server-side SDK for the current Subscriptions API, so any calls need to be done yourself with HTTPS.
Regardless, payers can update their payment methods and change to a different or new card via login to https://www.paypal.com , Profile, My Money, My Preapproved Payments