Swift libraries used to be pakaged when creating the ipa on 2.3.16 and before even when <swiftSupport /> was not added to robovm.xml. 2.3.18 appears to have changed this to default to not copying them unless especifically indicating it which may break backwards compatibility by crashing on devices < 11.2.

I think this is quite critical for anybody that has upgraded to 2.3.18 and is not aware of this as, according to my test, the AppStore will not reject the binary and the crash will occur in production.