Customers receiving an iPhone 18 Pro, iPhone 18 Pro Max, an Apple Watch Series 12, or an Apple Watch Ultra 4 tomorrow will need to install a software update right away. The iPhone 18 Pro and iPhone 18 Pro Max ship with iOS 27 variants with a 24A427 or 24A8428 version number. The launch version of iOS 27 is version 24A437, so if you're getting an iPhone 18 Pro, expect a software update during the setup process.