It depends on the number of pages. In case you only need to include or exclude a few pages, then:
– for exclusions use this option: https://i.imgur.com/YTRq7Ra.png
– for inclusions a small custom snippet is needed: https://wp-dreams.com/knowledge-base/limit-results-to-specific-post-ids-only/
..if however there are dozens of pages, and possibly you are planning to add more, categorizing them and excluding based on categories is much better and more convenient way – as you won't have to add the new pages to the exclusion/inclusions list.
User search: it's basically an option to exclude selected users from the results. If you need this feature, you can of course update, otherwise it might not be neccessary.
The options are not changed upon minor updates. On bigger changes some options may be replaced, and can be re-verted to their default states. Recently the redirection options were re-worked, I've of course added a fall-back script to change the options according to the previous version installed. Some users still experienced changes there, and those specific options had to be configured again. All others stayed untouched though.
I always recommend doing a full-site and database back-up before doing plugin updates, mostly because if the update process fails or gets terminated by accident, you can end up with a site malfunction – and of course you can always restore that safely, if something does not work out. It should not happen at all, but you never know.
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