# iOS vs Android Feature Parity Matrix

**Purpose:** Feature-by-feature comparison of iOS and Android implementations to track parity gaps.  
**Owner:** Development Team  
**Last Updated:** 2025-12-22  
**Status:** active

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## Storage & Persistence

| Feature | Android | iOS | Notes |
|---------|---------|-----|-------|
| Persistent state | ✅ SQLite (Room) | ✅ CoreData + SQLite | Both implemented |
| Schema versioning | ✅ Room migrations | ✅ Explicit | iOS has explicit version tracking in CoreData metadata (P2.1 complete) |
| State survives app restart | ✅ Yes | ✅ Yes | Both implemented |
| State survives OS kill | ✅ Yes | ✅ Yes | Both implemented |
| State survives reboot | ✅ Yes | N/A | iOS handles notifications automatically |

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## Notification Scheduling

| Feature | Android | iOS | Notes |
|---------|---------|-----|-------|
| Exact alarms | ✅ AlarmManager | N/A | iOS uses UNUserNotificationCenter |
| Daily rollover | ✅ Automatic | ✅ Automatic | Both implemented (iOS uses NotificationCenter pattern) |
| Schedule persistence | ✅ Database | ✅ UNUserNotificationCenter | iOS OS-guaranteed |
| Next notification retrieval | ✅ getNotificationStatus() | ✅ getNotificationStatus() | Both implemented |

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## Recovery & Resilience

| Feature | Android | iOS | Notes |
|---------|---------|-----|-------|
| App launch recovery | ✅ ReactivationManager | ✅ ReactivationManager | Both implemented with persistence |
| Boot recovery | ✅ BootReceiver | N/A | iOS handles automatically |
| Missed notification detection | ✅ Yes | ✅ Yes | Both implemented with persistent state |
| Recovery logging | ✅ Comprehensive | ✅ Comprehensive | Both have good logging |
| Invalid data recovery | ✅ Tested (TEST 4) | ✅ Tested (RecoveryTests) | Both have automated recovery tests |
| Rollover idempotency | ✅ Tested | ✅ Tested | Both verify duplicate rollover prevention |
| Migration safety | ✅ Tested | ✅ Tested | Both test unknown/missing fields |

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## Background Execution

| Feature | Android | iOS | Notes |
|---------|---------|-----|-------|
| Background fetch | ✅ WorkManager | ✅ BGTaskScheduler | Both implemented |
| Background notification | ✅ WorkManager | ✅ BGTaskScheduler | Both implemented |
| Execution time limits | ✅ Flexible | ⚠️ ~30 seconds | iOS has strict limits |
| Battery optimization handling | ✅ Documented | N/A | iOS handles automatically |

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## Error Handling

| Feature | Android | iOS | Notes |
|---------|---------|-----|-------|
| Error codes | ✅ Structured | ✅ Structured | Both have error codes |
| Error recovery | ✅ Yes | ✅ Yes | Both handle errors gracefully |
| Invalid data handling | ✅ Recovery tested | ✅ Recovery tested | Both have automated recovery tests: Android (TEST 4), iOS `test_recovery_ignores_invalid_records_and_continues()` and `test_recovery_handles_null_fields()` (see `ios/Tests/DailyNotificationRecoveryTests.swift`) |

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## Testing

| Feature | Android | iOS | Notes |
|---------|---------|-----|-------|
| Unit tests | ✅ Yes | ⚠️ Partial | iOS has some tests |
| Integration tests | ✅ Yes | ⚠️ Partial | iOS has some tests |
| Test automation | ✅ High | ⚠️ Medium | iOS has manual components |
| Recovery testing | ✅ Yes | ✅ Yes | Both have automated recovery tests (DailyNotificationRecoveryTests.swift) |
| Combined edge case tests | ✅ Yes | ✅ Yes | Both have 3 combined scenarios: Android `test_combined_dst_boundary_duplicate_delivery_cold_start()`, `test_combined_rollover_duplicate_delivery_cold_start()`, `test_combined_schema_version_cold_start_recovery()` (see `android/src/test/java/com/timesafari/dailynotification/DailyNotificationRecoveryTests.kt`); iOS equivalent tests (see `ios/Tests/DailyNotificationRecoveryTests.swift`) |

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## Summary

### Critical Gaps (P0)

**None** - All critical gaps addressed:
- ✅ iOS rollover implemented (NotificationCenter pattern)
- ✅ iOS recovery testing implemented (DailyNotificationRecoveryTests.swift)
- ✅ iOS persistence confirmed (CoreData + SQLite)

### Important Gaps (P1)

1. **Test Automation** - iOS tests can be run via xcodebuild, but CI integration may need macOS runners

### Nice-to-Have (P2)

1. **OS Reboot Testing** - True OS reboot scenarios (iOS handles automatically, but explicit testing may be valuable)

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**Last Updated:** 2025-12-22 (P2.3 complete)  
**Next Review:** After next major milestone

