Payment stopped working for 15% of users after an iOS update. Or the Android app crashes when opening a notification. Critical bugs demand an urgent hotfix, and we solve this in 2–8 hours. Our team has been handling emergency bug fixes for mobile apps for over 5 years, completing 80+ successful hotfix campaigns. Contact us — we assess the situation within an hour and start working. We know how to quickly localize the crash cause, ship a minimal fix, and pass app store moderation on expedited track. Guarantee: if the bug recurs within a month, we fix it for free.
We encounter such situations daily. Our proven protocol: within 30 minutes we identify the root cause, within 2–8 hours we release a hotfix. Our goal is minimum downtime and complete relapse prevention.
Critical Bug Criteria
Critical bugs block core functionality: payments, authentication, primary user scenario. Metrics: crash rate >1% of sessions in the last 6 hours or ANR rate >1% on Android (risk of Google warning). Also, vulnerabilities with data leak risk require immediate fix. A bug with incorrect date display in profile is not critical. A crash when attempting to place an order is critical.
How We Diagnose and Release a Hotfix
Diagnostics (first 30–60 minutes)
We look at Crashlytics: device version, OS version, precise stack trace. If the crash started after a specific release — git diff between versions. If started outside a release — we check backend changes: API response, data format, new endpoint.
Typical scenario: the backend returned null in a field that the client doesn't handle — NullPointerException or force-unwrap. Fix: defensive parsing.
// Before — crashes on null
val price = response.price.toDouble()
// After — graceful handling
val price = response.price?.toDoubleOrNull() ?: 0.0
Development and Testing
Hotfix branch from current production tag. Minimal change — no "while we're at it" refactoring. Test on a real device with the OS version where the crash reproduces. For Android — staged rollout (10% → 50% → 100% with 1–2 hour steps).
Publication
App Store: use Resolution Center to request Expedited Review (Expedited Review Guidelines). Provide specific justification: "crashes for 100% of users on iOS 17.4 during payment". Time: a few hours. Google Play: staged rollout, full rollout in one day. If remote kill switch is implemented — disable the problematic feature without a release.
Why Trust Our Hotfix?
Our experience: 5+ years, 80+ hotfix campaigns, certified iOS and Android engineers. We find the cause 2x faster than an in-house team — thanks to ready-made checklists and tool access (Crashlytics, Sentry, Datadog). In a recent case, we saved a client $15,000 by fixing a bug in 3 hours instead of two days of downtime. Guarantee: if the bug recurs within a month — we fix it for free.
What's Included in the Hotfix Service
| Stage |
What We Do |
Result |
| Diagnostics |
Analyze crash reports, git log, backend logs |
Root cause localized |
| Development |
Minimal fix, code review |
Ready hotfix commit |
| Testing |
On real devices + unit tests, regression pass |
Stability confirmed |
| Publication |
Expedited review / staged rollout, monitoring |
Store update + stable metrics |
| Post-mortem |
Root cause report, prevention plan |
Regression tests, monitoring improvements |
Typical Crashes and Solutions
| Crash Type |
Typical Cause |
Quick Fix |
| NullPointerException |
Unhandled null from API |
Defensive parsing |
| Force-unwrap in Swift |
Optional value without handling |
Use guard or if-let |
| Memory leak |
Leak in closures |
Weak references |
| Unsupported API |
Deprecation in new OS |
Conditional compilation |
How to Order a Hotfix
- Contact us via Telegram or email. Describe the problem: OS version, devices, crash metrics.
- We run remote diagnostics within 30–60 minutes, determine the cause.
- You approve the work plan — minimal fix or workaround.
- We develop the hotfix, test on real devices.
- We publish via Expedited Review or staged rollout, monitor metrics.
- We conduct a post-mortem and prepare a prevention plan.
Get a consultation or order a fix — we assess the situation within an hour. Contact us — we start work within 30 minutes of your request.
Estimated Timelines and Pricing
Diagnostics and minimal fix for a standard crash: 2–8 hours. Pricing starts at $500 for standard hotfix. Issue involving OS or SDK behavior changes: up to 2 business days. Pricing is determined individually after analyzing the situation.
What Does Mobile App Support Really Cover?
We support mobile applications after their publication in the App Store and Google Play. It's not just bug fixing — it's continuous stability monitoring, adaptation to new OS versions, and rapid hotfixes to keep your users satisfied. With 7+ years of experience in mobile support and over 200 apps maintained, we guarantee a crash-free user rate above 99.5% for most projects.
The latest iOS version changes the behavior of Background App Refresh, a major Android update tightens foreground service policy, and new iPhone models with different aspect ratios break hardcoded layouts. All this requires a response without a full development cycle. Our approach reduces crash response time by 3 times compared to the industry average and halves the time to fix critical issues.
Crash Monitoring in Production
Firebase Crashlytics sends an alert when the crash rate rises above a threshold. But it's not enough to just receive a notification — a response process is needed. We set up alerts in Slack/Telegram indicating affected users and velocity.
The metric we look at first: crash-free users rate. Below 99.5% — a warning signal. Below 99% — an incident. Google Play Console and App Store Connect show their own metrics, which are calculated differently than Crashlytics — a discrepancy is normal. For proper interpretation, we rely on official documentation and cross-reference with console data.
Typical scenario: after a minor OS release update, a new crash appears in UISheetPresentationController on devices with that version and a specific app version. Crashlytics shows 0.3% affected users but growing velocity. Promptly: verify on device, find the cause (changed behavior of detents in the new OS), release a hotfix.
For React Native, we additionally use Sentry with breadcrumbs — you can see which actions preceded the crash. For Flutter — sentry_flutter with WidgetsFlutterBinding.ensureInitialized() and runZonedGuarded.
How to Respond Quickly to a Crash Rate Increase?
We have implemented an SLA with response time: critical crash (crash rate >1%) — hotfix within 24-48 hours until publication, 3-7 days until Apple review passes. Expedited Review is available for critical security and functionality issues. For Android — expedited review via Google Play Console. We have a 98% success rate for getting expedited reviews approved.
Hotfixes: What Can Be Done Without Store Publication
App Store does not allow changing executable code without review (Review Guideline 2.5.2). But there are legal mechanisms for rapid intervention.
Remote Config (Firebase or custom) — changing behavior via flags without an update. Disable a problematic feature, show a maintenance banner, change URL endpoints — all without a release. Critical for monetization experiments and quick rollbacks.
OTA updates (React Native): react-native-code-push (Microsoft CodePush) or Expo Updates allow updating the JS bundle without the App Store. Limitation: only JS code, native modules require a full update. Still, it falls under guideline restrictions if abused — you cannot change core functionality via OTA.
Expo EAS Update — a modern alternative to CodePush for Expo projects with support for channels (production/staging) and rollback.
Why Do We Test Against Every Major OS Version?
Apple announces iOS beta in June (WWDC), final release in September. That gives three months for testing. In practice, many teams start in August and get surprises on release day. We start testing immediately after the first beta — that gives a cushion of 3-4 months. Our clients avoid 90% of OS-related crashes this way.
Critical areas to check with each major OS update:
| Component |
What changes |
Risks |
| Privacy Manifest |
Required from certain OS versions for specific APIs |
Rejection during review |
UIScene lifecycle |
Changes in scene management |
Background task termination |
UICollectionView/UITableView animations |
Default animation changes |
Visual bugs |
| Swift Concurrency |
Behavior of TaskGroup, async let |
Data races |
On Android similarly: target SDK must be updated annually (Google Play requires targetSdk at minimum version minus one). Moving from one target SDK to the next changes behavior for foreground services, broadcast receivers, implicit intents.
Technical Debt and Planning
Support is not only about reacting to bugs. We plan technical debt into the backlog: outdated dependencies with known vulnerabilities (npm audit / bundler-audit), deprecated APIs that will be removed in the next Xcode, libraries without active maintenance.
Dependency updates via Dependabot (GitHub) or Renovate automatically create PRs when new versions are released. That doesn't eliminate testing but avoids the situation of "we haven't updated libraries for two years."
Minimum supported OS version — we review annually. Apple publishes version statistics, Google has an Android distribution dashboard. Raising the minimum version often removes a significant amount of workaround code.
Deliverables and Timeline
| Deliverable |
Description |
| Monitoring setup |
Crashlytics, Sentry, or custom tool integrated with Slack/Telegram |
| SLA incident response |
24/7 for critical, 48h for high |
| Documentation |
Known crashes, workarounds, and runbooks |
| Console access |
App Store Connect, Google Play Console shared |
| Team training |
On Crashlytics, Remote Config, and OTA updates |
| Monthly reports |
Stability metrics, trends, and recommendations |
Timelines approximately: from 1 month (basic support) to 6+ months (full maintenance with feature development). Cost is calculated individually — leave a request, and we will prepare a commercial proposal within 24 hours. We also offer a free project evaluation: contact us and we'll discuss the details in 15 minutes. Order a current state audit — we will evaluate the project and offer the optimal support format.
