I get the purpose of the betas (Xcode 11, iOS 13 etc) is to build and test for when iOS 13 is released.
At what point should I stop developing for iOS 12 and switch to the betas?
Example, if I'm planning to publish an app in June 2019 then should I use Xcode 10 and design for iOS 12? Or will anything I build in Xcode 11 for iOS 13 also work in iOS 12 and therefore I can switch to the betas now?
Thanks in advance.
For June 2019 publishing, stay with 10.2 of course.
11 should be available this fall, with IOS13.
Usuing XCode 11 at this stage is more for preparing (analyse what you want to add to your app, like black mode) and see how to plan modification of code.
So, don't rush today to give up your production code…
As a personal approach, I wait for the second realse (aka 11.1) to move production code.
As you note, testing your app(s) against betas allows you to stretch goal your efforts and be ready when the trigger is pulled on their release, but if you're unfamiliar with such practices, it might be best to take it slow.
Keep in mind you can't submit apps using beta tools/SDKs, so any work against them will be forced to wait for release products.
Any release you have for June would be best kept aligned with current release tools/SDKs, not betas.
Apple will let us know when Xcode 11.x is allowed for the store.
Do use Xcode 11! I found it to be almost unusable and have given up until it is more stable.
