Apple released iOS 17.5.1 to fix a bug that caused deleted photos to reappear in the Photos app. This was due to a database issue.
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Apple is more focused on iOS 18 developer beta versions. Apple is also testing iOS 17.6, which is expected to be released soon and will be the last update in this version. After that we can expect iOS 18 in September.
Last week, Apple also released the second round of public betas for iOS 17.6 and iPadOS 17.6.
iPhone users running iOS 17 can look forward to bug fixes and security improvements in the update. In other words, don't expect any major changes or new features.