> - The stdlib (Foundation) is not identical on all platforms even today. This has been a major thorn as releases constantly have discrepancies and subtle bugs that are hard to diagnose and track down. Even Swift 6.1 broke non UTF-8 string encodings by just returning "nil" on Linux and took until Swift 6.2 to be fixed (nearly a year).

sad, I was doing server side around v4/5 and this was the biggest issue at the time for me (lots of stuff was not implemented and you only found out at runtime). that this is still a problem is very disappointing...