I have my ‘desktop category page style’ set to category and latest topics. Is there a way to change the topic summary to most recent post or most recent unread? The summary, at present, is the first post and I’d love something that showed the latest post.
Hello,
Sorry I am not sure about this. 
Can you tell more information what you want to achieve exactly? Some screenshot would be helpful too… 
The Categories and Latest Topics setting is ordered by the latest activities (posts).
The topic summary inside a topic is I think a different thing and not what you mean by summary? 
When I go to my default view…
The topics (eg General Things of Interest, Fiddle News Rough Drafts…) have summaries that are from long ago.
Is there anyway to display recent activity under that topic when viewing ‘latest’?
For instance, here is a recent post under one of those topics I’d love to have displayed as the summary…
Perhaps this is not how topics and categories were designed to be used.