PayPal’s acquisition of payments upstart Braintree appears in recent days to be more of a certainty.

But that didn’t stop Braintree’s CEO, Bill Ready, from lambasting PayPal at a recent, exclusive conference.

The criticism came at a financial technology event hosted by Goldman Sachs & Co. just last week. At the invitation-only event, Ready called the technology at PayPal, an eBay subsidiary, outdated. He also questioned the company’s metrics and said its days as the leader in payments are numbered.

Ready gave PayPal’s US user base as roughly 65 million, and said that Braintree, currently at 40 million, would pass it within the next 12 months. PayPal says it has “132 million active accounts in 193 markets and 26 currencies around the world.”

As for PayPal’s IT platform, Ready described it as “more than 10 years old” and not suited to today’s mobile-first world.

Published reports have PayPal acquiring Braintree for perhaps $1 billion. Ready has declined to comment on the rumors beyond this blogpost on Braintree’s site.