Now, Mark Gurman claims that iOS 18 will be one of the biggest, if not, the biggest update for iPhones ever (via MacRumors). While the analyst said that he will reveal features and changes that will make the update the most significant, we already know two features that might make iOS 18 a huge deal.iPhones could get support for RCS with iOS 18The first will be the support for Rich Communications Services (RCS). In November 2023, Apple announced that it would adopt RCS for iOS “later this year,” which is also when iOS 18 is expected to arrive. So, it is very likely that Apple will offer RCS to iPhones with iOS 18.RCS is a messaging standard, just like how SMS and MMS are. However, in comparison to those standards, RCS brings many new features, including read receipts, typing indicators, higher-resolution images and videos, and audio messages. Android already supports RCS with Google Messages. So, conversations between Android devices using Google Messages have those features. Since iPhones don’t support RCS, conversations between Android and iOS devices don’t have those features. But that’s going to change soon.Siri with generative AI could arrive with iOS 18The second feature could be an improved version of Siri with support for generative AI. In October 2023, Mark said that GenAI-powered Siri should “improve how both Siri and the Messages app can field questions and auto-complete sentences, mirroring recent changes to competing services.” Reportedly, Apple has also explored generative AI for other platforms, including Apple Music, Keynote, Pages, and even Xcode.