Updated March 25 with further analysis of exactly when iOS 18.4 is likely to be released.
Apple’s next big iPhone update will be iOS 18.4, unless there’s a bug-squishing exercise to sort out a recent software problem, an iPhone 16e issue or a mild nuisance with Apple Intelligence before then. Apple almost never says when an update is coming, but this time around, it’s dropped a lot of hints. And now the Release Candidate of the software had landed, which may clarify things further: details below.
As pointed out by Ryan Christoffel at 9to5Mac, the last big software release for iPhone was iOS 18.3 back in January, so we’ve been waiting a while here. Of course, there were smaller updates, iOS 18.3.1 and the most recent iOS 18.3.2, squishing bugs in the meantime.