If you love Confluence shortcuts and use h1. My heading as a shortcut and discovered it no longer works, you are not the only one. It took a bit of searching to find out if “h1 in confluence still work?” The actual search term would be “Confluence Wiki Markup for Headings doesn’t work”.
The docs have been updated but it is still frustrating.
Now instead of typing h1., you have to prefix the text with the pound or hash symbol. So, h1. Table of Content would be # Table of Content.
The more hashes you use, the lower the heading so ## is the equivalent of h2 etc. Now you know, go and check it out.
Note: this is relevant for Confluence cloud. Not sure about server but I would assume so.