Resolved after 9 hours 15 minutes, on April 16, 2026.
### **Dates:** Thursday, April 16th 2026, 00:00 UTC – 09:15 UTC ### **What happened:** Live and automated tests on iOS 17.0 simulators failed to start in both the EU and US-West data centers. Customers running tests on iOS 17.0 Intel-based simulators were unable to execute their tests for approximately 9 hours. ### **Why it happened:** A deployment introduced an incompatibility affecting iOS 17.0 on Intel-based infrastructure. The issue was not caught prior to release due to insufficient post-deployment test coverage for that specific simulator configuration. ### **How we fixed it:** We performed a rollback to the previous deployment, which restored full iOS 17.0 simulator functionality. ### **What we are doing to prevent it from happening again:** We are reviving and expanding automated post-deployment tests to cover a broader range of simulator configurations, including legacy Intel-based iOS versions, to catch incompatibilities before they reach production.
Update timeline
- resolved Apr 16, 2026, 10:10 AM UTC
Between 02:00 and 11:15 CEST, live and automated tests on iOS 17.0 simulators were failing to start in the EU and US-West Data Center. We executed a deployment rollback, which restored services. All systems are now fully operational.
- postmortem May 08, 2026, 06:42 PM UTC
### **Dates:** Thursday, April 16th 2026, 00:00 UTC – 09:15 UTC ### **What happened:** Live and automated tests on iOS 17.0 simulators failed to start in both the EU and US-West data centers. Customers running tests on iOS 17.0 Intel-based simulators were unable to execute their tests for approximately 9 hours. ### **Why it happened:** A deployment introduced an incompatibility affecting iOS 17.0 on Intel-based infrastructure. The issue was not caught prior to release due to insufficient post-deployment test coverage for that specific simulator configuration. ### **How we fixed it:** We performed a rollback to the previous deployment, which restored full iOS 17.0 simulator functionality. ### **What we are doing to prevent it from happening again:** We are reviving and expanding automated post-deployment tests to cover a broader range of simulator configurations, including legacy Intel-based iOS versions, to catch incompatibilities before they reach production.
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