Guides

Mobile SDK 4: What's New

Mobile SDK 4 introduces a new architecture that unifies web and mobile payment flows under a single transaction model based on Transactions API v2.

This shift simplifies integrations, ensures consistent behavior across platforms, and enables capabilities that were not possible in previous versions. It also lays the groundwork for future enhancements, including broader payment method support and more flexible transaction handling.

While version 4 already supports the most commonly used payment methods, we are actively working toward full feature parity with the 3.x SDK line, with additional functionality planned in upcoming releases.

What’s exactly new

Unified transaction model

At the core of version 4 is the transition to Transactions API v2, introducing a new transactionId that replaces the previous mobileToken.

All payment-related actions are now grouped under a single transaction – regardless of whether they originate from web or mobile. This enables:

  • A single /v2/transactions initialization request for all platforms
  • Reduced integration complexity (no platform-specific handling)
  • Consistent tracking across the entire payment lifecycle (including retries and refunds)

In addition, transaction status can now be queried during mobile payment flows, aligning mobile capabilities with those previously available only on the web.

Multiple payment attempts

Mobile SDK 4 supports multiple payment attempts within the same transaction.

If a payment attempt fails, the SDK no longer aborts the process. Instead, users can retry the same payment method or select an alternative payment method. This results in a smoother user experience and higher overall conversion rates.

Multi-attempt functionality is automatically enabled when two or more payment methods (including multiple card types) are provided in the server-to-server init request.

Consistent webhook behavior across all flows

Webhook behavior has been standardized across all payment scenarios. Webhooks are now consistently sent for:

  • Payments
  • Registrations
  • Authentication-only flows

Events are triggered for all relevant outcomes:

  • Success
  • Error
  • Cancellation
  • User abandonment / timeout

This provides a reliable and complete event stream, allowing backend systems to depend on webhooks instead of SDK callbacks for post-processing.

Integrated 3DS SDK

Version 4 includes a fully integrated 3-D Secure solution, providing:

  • Native authentication flows
  • Automatic app switching to banking apps where required
  • Reduced visual disruption during authentication

Frictionless flows occur more frequently and are optimized to minimize UI flicker. Soft-decline scenarios are also handled more seamlessly within the overall payment process.

Automatic transaction continuation (autoAuthorize)

The new autoAuthorize option allows transactions to automatically proceed after authentication or user confirmation, without requiring the user to return to the app.

This is particularly useful for flows involving external apps, ensuring that transactions can complete even if the user does not navigate back manually.

⚠️

Important: Only enable this option if you can reliably inform users about completed transactions outside the app.

For example, via notifications or backend-driven updates.

Mobile apps are often terminated while users complete authentication in external banking apps. If your app restarts without clearly communicating the transaction result, users may unknowingly initiate duplicate payments, making autoAuthorize counterproductive.

Modernized user interface and accessibility

The SDK UI has been updated with a modern design aligned with current platform standards.

Accessibility has also been improved to provide a better and more inclusive user experience.

What are the requirements to support the new SDK flow?

To start a transaction with Mobile SDK 4, you must obtain a transactionId from Transactions API v2 and pass it to your application. The previous mobileToken concept is no longer used.

→ This requires migrating your backend integration from Transactions API v1 to v2 for both mobile and web. See our migration guide for more details: Backend Migration: Transactions API v1 → v2

Do I need to upgrade soon?

We recommend upgrading once the payment methods you require are available in version 4.

There is no immediate need to switch, but Transactions API v2 is the strategic direction going forward, and future enhancements will be built on this architecture.

Will you still provide support for Mobile SDK 3.x?

Yes. We will continue to support the 3.x line of the Mobile SDK for the foreseeable future.

What payment methods are supported by the new SDK?

As of version 4.0.0, the following payment methods are supported:

  • Credit and debit cards
  • Apple Pay
  • Google Pay
  • PayPal
  • PostFinance Pay
  • Twint

Additional payment methods will be added in upcoming releases.

What versions of iOS and Android does the new SDK support?

  • The iOS SDK supports iOS 15 and above. Xcode 26.0.1 is required to build your app.
  • The Android SDK supports Android 6 (API 23) and above. Gradle plugin 9.1.1 is required to build your app.

I’m using a cross-platform framework to build my app, is there anything I should know?

We do not currently offer official support for cross-platform frameworks such as React Native, Flutter, or Xamarin.

This does not necessarily mean the SDK will not work in such environments. However, it is designed and tested for native iOS and Android applications, and support for cross-platform integrations may be limited.

I have a question that is still unanswered – where can I seek support?

Get in touch with us and we’ll be happy to help.

You can reach us at any time via our contact form.