Revert to previous IOS?

You can't go back. If you don't want messages saved for 30 days after deletion, you can go in and manually delete as many messages as you want to permanently delete them.

For what it's worth, saving deleted messages for 30 days was a top request from users prior to iOS 16.

Apple has never supported this.

Hello ~ As *Bob Timmons* wrote down grading is not supported. If you are having issues and can describe your problem perhaps we can help you.

~Katana-San~

You can suggest to apple they alter that fact by using their feedback channel

Feedback - iPhone - Apple

Hello again~ As with many changes sometimes it takes a bit of getting used to. I am not a fan of some of the changes myself but being able to save the messages for thirty days does have it’s good points and as *Bob Timmons” pointed out you can manually delete them. Are there any other issues we can help with?

~Katana-San~

Did you use the link above to tell Apple what you want?