Nowhere near as disruptive as having to re-install Discourse 
Just update Topic List Previews Theme Component within Settings → Customize.
In that list of Theme Components you should see TLP
Check for updates manually using the supplied button:
And follow the instructions.
Note if that checkbox is checked, it will also update if you upgrade Discourse.
See more here: Install a theme or theme component
btw If you are managing your own install you could also consider installing the Topic List Previews Sidecar plugin (see the OP of the linked Topic) for extra functionality.