?page_id=111 vs. ?p=111 in URL

What permalink structure are you using?

I’m using the “day and name” permalink (e.g. https://www.mysite.com/2013/03/04/sample-post). This is used for posts. I’ve always had this since v3.0.

What happens if you switch back to the default permalink structure?

After changing to the “default” permalink and removing the rewrite rules from .htaccess (as recommended), the ?p does not work, and ?page_id works.

Can we see the site using default permalinks?

https://dev7.hs.iastate.edu/?p=3495

vs.

https://dev7.hs.iastate.edu/?page_id=3495

Where is your main posts page on the site? https://dev7.hs.iastate.edu/?p=3495 is the url for a Post – not a Page.

Our site has been modified to use posts for news sorted by date, hence setting the “day and name” permalink. Our website’s pages are defined in such a way when we have a page ID 111 and permalink for that page is “…/test-page”, we get to “…/test-page” when we use ?p=111 (now ?page_id=111), and vice.

It’s odd that ?p=xxx used to work.

So this makes me think, does ?page_id= go to a page while ?p= go to a post?

Yes.