iOS, caching and switching from LazyCharacteristic to DiscoveredCharacteristic

[curioustechizen]

Not sure if any of this makes sense, but here goes:

In our Android and iOS apps, we have a notify characteristic that is used by the peripheral to send "responses". This has been working well for a while. We have been using characteristicOf() to obtain this characteristic, which we then call peripheral.observe() to then read data.

However, we observed some crashes in the wild. characteristicOf would crash both on Android and iOS with a NoSuchElementException, complaining that it cannot find the service.

So I switched to using the DiscoveredCharacteristic instead of characteristicOf (via the peripheral.services flow). On iOS, I had to use kable v0.40.0 and set forceCharacteristicEqualityByUuid = true for this to work.

Now this works well for new installs. However, on iOS, if I update the app from a previous version (which was using characteristicOf) to the version that uses DiscoveredCharacteristic, then my app never receives the ByteArray from my characteristic. So my BLE communication just plain broken. Even after restarting the iPhone etc. I suspect that when this happens my kable never delivers the results to my DiscoveredCharacteristic

Does anyone know if there is some iOS caching at play here?

[curioustechizen]

For anyone reading this - this was a bug introduced by me. The code branch that is run when reconnecting to a peripheral did not have the forceCharacteristicEqualityByUuid = true part set. Fixing this fixed the bug.

It was neither an iOS bug nor a kable bug. Closing this discussion.