4 ms·

You have to add all kinds of reference qualifiers (__strong, __weak, ...).

• plorkyeran 7y ago
  You don't have to explicitly mark things as strong as it's the default. Having to manually break references cycles with weak pointers does make the migration not as simple as just changing the compiler flags, but I've never heard of it being all that difficult. Apple managed to migrate Xcode in a single version.