The Customer Profile

The customer is an intermediate sized Healthcare Technology company in the United Kingdom that has launched a Mobile Patient Engagement Application. The application was built using the Xamarin.Forms 4.x development framework.

The application serves over 10,000 patients with access to locations through the National Health Service (NHS). The application allows patients to schedule appointments, receive medication reminders, use telehealth services and access their health record securely.

By mid-2023, the application was starting to show its age. It had been developed using Xamarin.Forms version 4.8 which was at its end-of-support lifecycle, meaning that there are no longer any capabilities, fixes or enhancements to the software.

Two major third-party libraries that the application depends on for its functionality had also been sunsetted by the vendors, leading internal developers to spend roughly 30% of each development sprint resolving compatibility issues and crashes with newer Android 13 and iOS 17 devices rather than building new features.

The customer reached out to Adequate Infosoft with a clearly defined requirement to migrate the application to a supported platform which would provide future capabilities, without disrupting patient access to the application or compromising HISPA-compliance or GDPR-compliance.

The Technical Challenge

The application was more than just a standalone CRUD-based application; it had amassed 4 years of complexity including:

• 14 different customised Xamarin Renderers specifically created to provide the brand experience users expect, including a custom appointment calendar, a medication tracker widget and a biometric authentication prompt.
• 6 different Third-party SDKs were integrated into the mobile application, including a telemedicine video SDK, a connector to either the NHS appointment and booking API, or the push notifications service, and assume they will be commercially supported with .NET MAUI; however, none of these third parties had confirmed that.
• An offline-first BI architecture built using SQLite with a complex synchronisation engine which was responsible for synchronising patient data.
• FHIR (Fast Healthcare Interoperability Resources) API integration to allow access to health records.
• High-security requirements including certificate pinning, biometric authentication, and local data encryption.

Our Approach

Week 1-2:

Audit and Planning Our team conducted a full technical audit and discovered that 3 of the 6 third-party SDKs had no published .NET MAUI support. For two of these, we identified community-maintained MAUI-compatible forks.

For the telemedicine SDK, we worked directly with the vendor's engineering team to obtain an early access build of their MAUI SDK, a relationship that benefited the client significantly.

All of the custom Renderers were cataloged and prioritized (14 Renderers in total). Eight had been classified as simple Handler conversions.

Four required some partial redesign of the UI, since the way the underlying MAUI control APIs worked had resulted in the need for redevelopment of the control. Two others were completely replaced by solutions in the MAUI Community Toolkit.

Week 3-5:

We created a single .NET MAUI project and moved all main parts of the previous application to that project - Dependency injection setup (DI), Navigation Service, SQLite Data Layer, and FHIR API Client. The offline sync engine is the same, with only minor modifications; it had a solid architecture, as well as a version of SQLite-net that is stable with MAUI.

The security layer required particular care. Certificate pinning was re-implemented using .NET MAUI's HttpClient handler pipeline. Biometric authentication was migrated to the Plugin.

Fingerprint library for MAUI, which provided consistent behavior across Android and iOS. Encrypted local storage was re-implemented using AesGcm from .NET's built-in cryptography library, replacing a Xamarin-specific implementation.

Week 5-8:

UI Migration and Handler Development XAML migration across the application's 34 screens was largely straightforward. The most significant UI work involved the custom appointment calendar widget.

The original Renderer-based implementation had accumulated years of platform-specific workarounds. Rather than doing a direct conversion, our team rebuilt it as a clean .NET MAUI Handler, resulting in a component that was both more performant and more maintainable than its predecessor.

Push notification integration was migrated to the Plugin.Firebase.CloudMessaging package for MAUI, with platform-specific notification channel configuration handled cleanly within the unified project structure.

Week 8 to 10:

Testing a healthcare application requires a lot more than standard functional and regression testing alone, our QA team also performed the following additional testing:

Data Migration Testing:

To validate that no patient records were lost/corrupted during updates to the SQLite schema, we performed complete data migration testing.

Penetration Testing:

We executed penetration tests on both the certificate pinning layer and the API security layer.

Access Testing:

We completed accessibility testing using both VoiceOver (iOS) and TalkBack (Android) to ensure compliance; we made 11 fixes for accessibility before releasing the app.

End-to-End Teleconsultation Testing:

We successfully tested the end-to-end teleconsultation workflow on 24 different device and OS versions.

The client's Clinical Governance Team performed User Acceptance Testing over a 2-week period before general release with 500 test patients as part of the phased rollout to ensure that the release meets its clinical governance requirements for safety and quality.

Results Delivered

The migrated application went live on both app stores simultaneously in Q1 2024, just weeks before Xamarin.Forms' official end-of-support date.

The number of crashes from the migrations were directly related to the patient safety issues because the patients who were relying on their medications to remind them were not receiving their reminders under the legacy Xamarin system. The reliability of reminder delivery has now increased to 99.6% since moving to the new platform.

According to the CTO of Client, the number of new features developed within the first two sprints after going live with the migration was greater than the number of new features developed by the development team throughout the prior 6 month period as the legacy Xamarin codebase had created an extremely large maintenance burden on the development team.

The system is live and liked by users. It is available on both the iOS and Android stores.