title: Will plain style permalinks continue to work after I change permalink settings?
body: <p>I've had my WordPress site for about a decade now, and originally I never set any custom settings for permalinks, so my permalinks are all of the form <code>/?p=123</code>.</p>
  
  <p>I'd like to start using permalinks that incorporate the post name in the URL. It looks easy enough to change this. It's my understanding that WordPress will likely update all my permalinks internally, but there exist a lot of external links to my site that point to existing permalinks, and I don't want those to stop working.</p>
  
  <p>Will WordPress keep supporting visits to old plain-style permalinks if I change the setting? It seems like it should be able to since it's just using a URL query param and the other permalink styles use the URL's path, but I don't want to assume it does and be wrong.</p>
  
  <p>And if this is not the case, is there a straightforward way I can set up the redirects? I have hundreds of posts and it would be tedious to make a manual redirect for each one. </p>