I\'m in the the process of replacing the Free and Standard paypal button with a Express checkout integration. I believe I\'ve done most of the work but I have 2 outstanding
I discovered that you can force the old layout by including a "force_sa=true" param in your payment request url. Can't find this documented anywhere, but it seems to work consistently. I asked pp tech support about it and got this response:
The new express checkout layout is being gradually rolled out, you may have an option to force the layout with the following redirection url format: 'https://www.sandbox.paypal.com/checkoutnow/2?token=' to force the new checkout layout, it does the same way as force_sa=true
Didn't answer my question, but I guess they acknowledged it's a valid way to force a layout and not be at the mercy of their "rollout".