Board Thread:Support Requests - Getting Technical/@comment-25118285-20160807201833

Hi, I was hoping to create some sort of site notice or site-wide message for my wiki, but I can't find any Help articles about how to create them. There are some old archived forum posts about it, but they all keep directing people towards "MediaWiki:Sitenotice", which I can't seem to find. Am I looking for help in the wrong place? Does the sitenotice page still exist? Any sort of guidance would be appreciated because I am only adept at the most basic Wikia code :B 