If you don’t enable the Multisite Configuration option and don’t enable the Sync Comment Data Webhook on any of your subsites, everything should function on your sites in the same way as it did before this update.
If you don’t enable the Multisite Configuration option, you can enable the Sync Comment Data webhook individually for each subsite. You can enable it for some subsites and leave it disabled for others. You’ll need to add a webhook, using the correct Payload URL on Discourse, for each subsite that you’ve enabled. The subsite’s Payload URL is available in the Sync Comment Data Webhook setting description on each subsite. Doing this might make sense if you are publishing to different Discourse categories from each subsite, or if only one or two of your subsites were displaying Discourse comments.
It will be possible to do this after the next update. I’ve added a filter that you can hook into to exclude particular subsites from the multisite configuration. That update will be available in the next couple of days.
If you run into any issues with the plugin’s multisite functionality, please let me know.