Will iOS update permanently delete Recently Deleted photos?

Rule one: Before any update Make a back up

If you don't want these images deleted, why are they in the Recently Deleted folder?

If you're not sure whether you want them deleted, why are they in the Recently Deleted folder?

This is like putting your cash in your office waste bin and wondering if the janitor will throw it out sometime.

So: the simple answer is, no it won't. But a: sometimes things go wrong, and b: you're telling the app you ant these images deleted. It will delete them sooner or later.

each photo in your Recently Deleted album should be showing the number of days, when it will be permanently deleted. Rescue your important photos, before the time is up.

If you want to get photos temporarily out of the way but not want to delete them outright, consider to use hide them, but do not trash them.

Are you using iCloud Photos? If you are low on iCloud Storage, any photo you delete may be instantly deleted permanently to help you free your cloud storage. Then it is very risky to put anything into Recently Deleted, without checking it very carefully, if you really want it to be deleted.