.</li>
<li>Each UPI payment app can listen to a payment request of the form <code>upi://pay?...</code> sent by a caller app to iOS.</li>
<li>The specification does not let you specify the target app's identifier in this request. On iOS, there is no other disambiguation measure available such as any ordering of the UPI payment apps that can be retrieved using any iOS APIs. Hence, it's impossible to know which UPI payment app will be invoked.</li>
<li>One of the applicable apps gets invoked and it processes t