MacRumors published a story that Apple has released the first betas of iOS 17.4 and iPadOS 17.4 to registered developers.

Apple Seeds First Betas of iOS 17.4 and iPadOS 17.4 to Developers

Apple today seeded the first betas of upcoming iOS 17.4 and iPadOS 17.4 betas to developers for testing purposes, with the updates coming a day after the launches of iOS 17.3 and iPadOS 17.3.

Registered developers are able to opt into the betas by opening up the Settings app, going to the Software Update section, tapping on the "Beta Updates" option, and toggling on the iOS 17 or iPadOS 17 Developer Beta. An Apple ID associated with a developer account is required to download and install the betas

Apple Seeds First Betas of iOS 17.4 and iPadOS 17.4 to Developers