Speaking of watchOS apps, it looks like developing a full fledged application running entirely on watchOS is not yet possible: there is no networking to speak of on watchOS. 😔
If you need anything beyond basic HTTP or CloudKit, the only option is
to use WatchConnectivity framework to funnel all networking through the extension
running on the iPhone. 😢
The only hope is that it will be added in the future.
On the topic of regressions in minor iOS updates, there was another one a bit ago on iOS 13.4 release, as I recall. That one was in the StoreKit API, and it has changed the way how failed transactions are being processed.
Normally, you have to finish every transaction passed into your
SKPaymentQueue delegate once you are done processing it, and that
includes failed transactions. However that wasn't the case on
iOS 13.3 and earlier releases: failed transactions did not require
finishTransaction: call and were removed from the queue even if they
were not acknowledged.
Starting with iOS 13.4 though, you have to acknowledge all transactions.
[[SKPaymentQueue defaultQueue] finishTransaction: transaction];