# Any Apple update can break our app. Here's how we find out first.

[Sentry](https://yomu.fyi/company/sentry) · Dan Mindru, Oleh Stasula · Jul 2, 2026

**Type:** Problem & solution

## Summary

Usage is an Apple ecosystem resource monitor that relies on undocumented APIs vulnerable to silent data structure changes across OS updates. To maintain stability across iPhone, iPad, and Mac without degrading device performance, the development team uses Sentry across separate component projects in a unified workspace. Beyond capturing standard crashes, the team wraps Swift errors with unexpected raw data payloads to quickly diagnose undocumented API structure drift while scrubbing sensitive user values. They also employ Sentry Size Analysis as a regression gate to monitor release payload deltas, preventing unintended asset omissions or bloat from slipping through code reviews. This multi-layered monitoring setup enables the team to detect and resolve platform-induced breakages before most end users encounter them.

## Context

Usage is an Apple system monitor that depends on undocumented APIs without deprecation notices, exposing the app to silent data structure changes across OS updates and hardware generations. In addition, its architecture spans multiple cooperating processes with distinct lifecycles, and manual reviews previously missed a refactoring error that removed a localization file and hurt active usage in production.

## Approach / What changed

The team separates monitoring across app targets into individual Sentry projects under a unified workspace. They capture non-fatal decoding errors using a Swift Error wrapper that attaches unexpected payload structures to Sentry extras while scrubbing private data. They also implement Sentry Size Analysis with delta alert monitors on every release build to detect missing assets or bloat, and instrument counters and gauges using Sentry Metrics.

## Takeaways

- Wrapping Swift errors to attach raw payload structures provides necessary diagnostic context to resolve undocumented OS schema changes that stack traces alone cannot explain.
- Separating multi-process app targets into distinct monitoring projects under a shared workspace ensures crash attribution to specific processes like background services and widgets.
- Tracking build size deltas between releases serves as a regression gate to catch missing localization files, dropped bundle assets, or unexpected binary bloat.

**Tags:** [iOS](https://yomu.fyi/topic/ios), [Monitoring](https://yomu.fyi/topic/monitoring), [Observability](https://yomu.fyi/topic/observability), [Performance](https://yomu.fyi/topic/performance), [Reliability](https://yomu.fyi/topic/reliability)

[Read original post](https://blog.sentry.io/apple-update-breaks-app)