Device transfer from other platforms to iOS is restricted because it violates the terms of AppStore.
If you want to do it by device changing, please contact me directly.
From v3.0.8, when "whether the game user is an iOS user or not" is changed from save data retention to server retention management, the new server management flag will be applied at startup after v3.0.8 release. Therefore, there is a problem that "a user playing iOS before v3.0.8 gets this error when trying to restore the account with the latest version".
In this case as well, I will handle your account manually, so please contact me directly.