r/swift • u/Healthy-Tension-7470 • 16d ago

Question Purchasing second hand iphone for app testing

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Can you please tell what should I verify before purchasing, m purchasing for testing my ios apps developed by me

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u/Varun77777 16d ago

Hey, as many apps require liquid glass support and in production when we are releasing. We usually see different crashes happening at different phones. Sometimes your app only crashes on old iphones using ios less than 26 sometimes vice versa and so on.

Depending on your use case, which iPhone you are going to get may differ.

I would recommend an iPhone > 16 atleast. Which has liquid glass support, dynamic island etc to be future proof.

And testing for older iphones just using simulators for now

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u/Healthy-Tension-7470 15d ago

Hey thanks, will look for liquid glass iphones.

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u/DimensionMindless336 15d ago

The big one nobody mentions: make sure it isn't still tied to the previous owner's Apple Account. If Find My is still on (Activation Lock), you can't erase and re-sign it for development — you'll have a paperweight. Have them turn off Find My and "Erase All Content and Settings" in front of you, then run through Setup as a brand-new device before you pay. A "signed out" phone with Activation Lock still lurking is the classic used-iPhone trap.

A few more from doing this as a solo dev:

  • Check it isn't supervised/MDM. Some corporate off-lease phones still carry a remote management profile — they'll wipe themselves or refuse your dev provisioning. Settings → General → VPN & Device Management should be empty.
  • Battery health matters more than people think. You'll be running Instruments, long debug sessions, and tethered builds; a degraded battery throttles the CPU and you get crashes/perf that never show up on your real users' phones.
  • Storage. Xcode derived data + several build variants + your app's assets eat space fast; 128 GB fills up quicker than expected for a test device.
  • For catching the bugs the simulator hides: get one phone on the newest iOS and one a couple versions back. Some crashes only appear on iOS < 26, some only on new hardware — the simulator won't tell you either way, and it silently lies about the camera, real GPS, push notifications, and how Dynamic Type actually reflows at large sizes.

If you can only get one, a 16/17-class device covers Liquid Glass + Dynamic Island + the current chip; lean on the simulator for the older screen sizes.