Client Overview
A national logistics company operating large-scale warehouses relied on rugged Honeywell CT40 and CT47 Android handheld scanners for critical operational tasks, such as inventory tracking and thermal label printing.
With Xamarin’s end-of-life approaching, the client sought to modernize their internal mobile application—preserving existing workflows while improving maintainability and ensuring compatibility with aging Android 9.0+ devices.
Flutter Project Summary
Keyhole Software was engaged to completely rewrite the mobile application in Flutter. Despite hardware and connectivity limitations, the consultant aimed to match all legacy functionality while introducing a more modern and resilient mobile architecture.
- Seamless functionality on Honeywell CT40/CT47 scanners (Android 9.0+)
- Reliable offline use in low-connectivity warehouse environments
- Preserved workflows to avoid retraining warehouse staff
- Future-proof replacement of deprecated Xamarin codebase
Solution
A single Keyhole Software mobile consultant led the development, supported by a part-time Keyhole project manager. The team worked directly with client stakeholders—spending time on-site in warehouses to gather feedback, validate functionality, and ensure seamless user adoption.
The new application was built using Flutter (v3.32.1) and Dart (v3.8.1), with special attention to Android 9.0+ compatibility. An offline-first architecture was implemented to support real-world warehouse scenarios where Wi-Fi or VPN access could be unreliable.
Key Technical Components
- Feature-for-feature rewrite of the legacy Xamarin application
- Offline-first design for resilient data sync and caching
- Thermal printer and barcode scanner integration via community-maintained Flutter plugins
- Kotlin configuration debugging (no native code development required)
- Reverse-engineered Xamarin logic and UI to minimize user disruption
Limited access to Honeywell hardware during development was mitigated with emulators, defensive coding, and use of Google Pixel devices for proxy testing. On-site hardware integration was scheduled for three days but completed in just two, thanks to thorough planning and execution.
Results
- Delivered a month ahead of schedule, saving over 150 estimated development hours
- Seamless transition away from Xamarin with no user retraining required
- Significant offline improvements despite hardware constraints
- Reduced long-term technical debt with modern Flutter architecture
- Internal testing version released with full functionality and only minor bugs
Technologies Used
- Flutter (v3.32.1)
- Dart (v3.8.1)
- Android 9.0+
- Honeywell CT40 / CT47 Handheld Scanners
- Community-supported Bluetooth & thermal printer plugins
- AS400 backend system accessed via VPN-secured APIs
- Kotlin (configuration/debugging only)
Why Modernize from Xamarin to Flutter?
As Xamarin reached deprecation, the client needed a future-ready mobile platform. Keyhole Software delivered a full rewrite in Flutter, offering improved performance, simplified long-term maintenance, and full feature parity with the original system—ensuring minimal disruption to daily warehouse operations.
Technical Highlights
- Stack: Flutter (v3.32.1), Dart (v3.8.1), Kotlin config for native Android compatibility
- Devices: Honeywell CT40 / CT47 scanners running Android 9.0+
- Legacy integrations: Barcode scanners, Bluetooth thermal printers
- Backend: AS400-based APIs over VPN
Native Integrations Using Flutter
Without official Flutter plugins for Honeywell hardware, the consultant used community-sourced packages and debugged Kotlin-level build configurations to achieve stability—without adding custom native modules. This enabled seamless Bluetooth printing and barcode scanning on aging warehouse hardware.
Reverse-Engineering for Seamless Adoption
Although new to Xamarin, the consultant reverse-engineered the deprecated codebase to ensure the Flutter replacement mirrored existing behavior and UI. This minimized change for warehouse staff and eliminated retraining costs.
Offline Support on Legacy Hardware
A key improvement was the addition of robust offline capabilities. Data caching and synchronization logic ensured the app worked reliably—even on legacy Android hardware in areas with limited or no connectivity.
Lean Team, High Impact
This high-performing engagement was executed by a single mobile consultant and part-time project manager. Their client-facing, agile approach allowed them to deeply understand stakeholder needs—through regular demos, warehouse visits, and transparent collaboration.
As a result, the project exceeded expectations: integration was completed a day early, and the product was delivered weeks ahead of schedule with fewer development hours than projected.
Flutter and Xamarin Expertise
Keyhole Software offers deep expertise in Flutter mobile development and Xamarin modernization. We help enterprise teams evolve their mobile apps with modern, scalable platforms—without disrupting users or workflows.
