MyBB Community Forums

Every page on my forum shows up as an older cached version unless you refresh the browser window. This happens to all my users. For example, if you click on the last post link for a thread it goes to an older post, if you refresh the new posts appear. If someone adds a new thread or forum it does not show up unless you hit refresh. Even after hitting refresh, if you navigate back to that page you may still need to hit refresh for that same content to appear.

I am using the newest version of MyBB

You could give the "Recount & rebuild" tool a try. (You can find it under "Tools")

Just a wild shoot, using Cloudfare or something similar that can display cached page?
Not for post, but I faced the same thing while modifying stylesheets, it doesn't affect instantly until you put Cloudfare in dev mode.

I am not using Cloudfare.

Literally everything on my site is displaying outdated content unless you refresh. Even after you post you have to refresh the browser for it to show up