However, the parameters to these methods are not equivalent. Specifically, the update_payment_method API accepts a redirect_url parameter, while the other one doesn't.
While interesting in it's own right, this doesn't match what's mentioned in the documentation which does mention in the 10th row in that table that Checkout V3 supports redirect urls.
And since we want to deploy soon and there doesn't seem to be a solution to this problem, how do I revert back to Hosted Pages V2, if possible, so I can use the older API and the dear redirect_url?
Thanks for writing to us.
Unfortunately, it is not possible to use the “redirect_url” parameter in the “Manage payment sources” API (Checkout V3). You can only use the “redirect_url” parameter in the “update payment method” API (Checkout V2).
Alternatively, to redirect your customers to another web page, you could use the JS “success” call. If you still want to switch back to the checkout V2, kindly let us know and we can enable it from the back end.
Please let us know for any further queries.