Fix & Enhance Existing Android Java App – Bluetooth Printer, Break Timer

I have an existing Android application written in Java. The complete Android Studio source code is available and the application is already working in production. I need an experienced Android Java developer to make several specific fixes and small enhancements. This is not a new app development project. Main tasks: 1. Bluetooth thermal printer compatibility - Existing NETUM NT1809 printing must remain unchanged. - Add/fix support for a PT210 ESC/POS Bluetooth printer. - Main issue is formatting/font behavior of the Defect Tag, Minus-Carton Tag. - Physical printer testing may need to be coordinated with me. 2. Fix EXTRA carton status - EXTRA status currently carries over to following inspection records. - EXTRA must belong only to the applicable record/carton. 3. Prevent report file overwrite - Existing SMB upload can overwrite an existing Excel report. - If filename already exists, automatically create -01, -02, etc. 4. Upload report is only an icon, add word: "upload report" 5. Fix/refactor Pause/Break function - Correct pause timing and Cancel behavior. - Support more than two pauses. - Pause must survive navigation between activities. - Correct handling of pauses longer than 59 minutes. - Break reason and Excel/report output must remain consistent. 6. Logout completion check - Before logout, check whether planned inspection quantity/tasks are completed. - EXTRA cartons must be counted separately. - Show completion summary or incomplete-plan comment prompt. 7. Configurable SMB folders - Allow separate configurable subfolder/path for Plan Download and Daily Report Upload. Important A detailed source-verified change request will be provided. It includes existing methods/code areas, required behavior and acceptance tests. I am looking for someone who will modify the existing application carefully, not rewrite it. Existing unrelated functionality must remain unchanged. Deliverables - Updated complete Android Studio source code - Working/signed test APK - Short list of files/methods changed - Regression testing of the requested functions - No source code obfuscation or dependency on the developer after completion Required skills Android Java, Android Studio, ESC/POS Bluetooth printing, SMB/file handling, SharedPreferences, Excel/JXL handling, debugging existing applications. Please bid only if you are comfortable working with an existing Java Android project. When applying, please briefly describe your experience with ESC/POS Bluetooth printers and debugging existing Android Java applications. Generic copy/paste proposals will not be considered.