when there will be new update?

If you mean when will the next update to iOS 16 be released, it will be when Apple has finished testing it and considers it ready. No one here would know when that will be. If you are asking when iOS 17 will be released, Apple has said "Autumn" which would be any time between September 21 and December 21, 2023. In the past, Apple has often released the new version of iOS at the end of September. That, however, is no guarantee they will do it at that time this year.

When Apple chooses to release one.